How to Make an Invoice: A Step-by-Step Guide (2026)

An invoice is a formal document a seller issues to a buyer to request payment for goods or services, and making one requires eight standard elements: your business details, client details, a unique invoice number, issue and due dates, itemised line items, a subtotal and total, payment terms, and accepted payment methods.

Most small businesses can make a professional invoice in 3–5 minutes using a template, a free online generator, or invoicing software. Doing it in Word or Excel from scratch takes around 10–15 minutes the first time. Whatever tool you choose, the process below works everywhere — the eight elements are the same in the US, UK, Australia, and the EU.

What is an invoice?

An invoice is a formal commercial document issued by a seller to a buyer that requests payment for goods or services and records the transaction for tax and bookkeeping purposes.

An invoice has three jobs. It tells the client what they owe, creates a legal record of the transaction, and triggers the client’s accounts-payable process so the payment actually happens. Without one, most B2B clients will not pay — their finance teams need an invoice to open a payment file.

Invoices are distinct from receipts: an invoice is issued before payment and requests it; a receipt is issued after payment and confirms it. For the full side-by-side breakdown, see our guide to the difference between an invoice and a receipt. Invoices also come in several varieties — standard, proforma, recurring, credit note, commercial — each with a specific use case, covered in our guide to the 20 most important types of invoices.

The 8 essential elements every invoice must include

Every professional invoice must include eight standard elements: your business details, the client’s details, a unique invoice number, the issue and due dates, itemised line items, a subtotal and total, the payment terms, and accepted payment methods.

Miss any one of these and the invoice risks being rejected, delayed, or disputed. Below is the anatomy — with the rule for each element and one example. For the deep dive on each field, see the complete invoice anatomy guide.

1. Your business details

Include your trading name, address, business registration number (if you have one), email, and phone. If your business is VAT-registered, include the VAT number here. Sole traders should use their full legal name.

2. The client’s details

Full legal business name, billing address (not necessarily the trading address), the specific contact person in their accounts-payable team, and their email. Confirming the accounts-payable contact with a new client before the first invoice is the single fastest way to avoid “it went to the wrong person” payment delays.

3. A unique invoice number

Every invoice needs a unique identifier in a consistent format such as INV-2026-0001. The format can be sequential, year-sequential, date-based, or client-prefixed. For the full breakdown of six valid formats and the legal rules in each country, see our full guide on what an invoice number is. Never reuse an invoice number, even across tax years.

4. The issue date and the due date

Two separate dates. The issue date is the day the invoice is created and sent. The due date is when payment is expected. Use an explicit calendar date for the due date (“Due: 15 May 2026”) rather than just “Net 30” — specific dates produce faster payment. For a full explanation of payment-term options, see the guide to invoice payment terms.

5. Itemised line items

One line per product or service. Include a specific description (“Brand strategy workshop, 4 hours”, not “consulting”), the quantity or hours, the unit price, and the line total. Vague descriptions are the single most common cause of invoice rejections in accounts-payable systems.

6. Subtotal, tax, and total

Show the subtotal of line items, any applicable tax (VAT, GST, sales tax) as a separate line with the rate shown, and the grand total in bold or a larger font. Tax line must be shown even if the rate is 0% — it demonstrates that you checked. For full professional layout conventions, see what a professional invoice template looks like.

7. Payment terms

State the number of days the client has to pay (Net 15, Net 30, Due on receipt), any early-payment discount, and any late-payment fee. “1.5% per month on overdue balances” is enforceable in most jurisdictions and materially improves on-time payment rates.

8. Accepted payment methods

Tell the client exactly how to pay you. Bank transfer (with account number and sort code or IBAN/SWIFT for international), card payment, a direct payment link, PayPal, or any other method you accept. Invoices with a clickable payment link get paid notably faster than those that require the client to set up a transfer manually.

What Does an Invoice Look Like?

Next, let’s look at what “invoice” means when put into practice, or better yet, how it looks. Invoices have to contain a lot of important information to be legally binding. Below, you’ll find everything you should include on your invoice – numbered and explained accordingly.

1. Invoice Number & Name:
   Each invoice must include a unique identification number. Typically, this combines the year and the invoice’s number (i.e., 2023001).
   Furthermore, depending on the customer’s country of origin, you may need to use a different name for the invoice according to local legislation — for example, VAT invoices in the UK or tax invoices in Australia and New Zealand.
2. Your Business Information:
   All your invoices must include your business information, including your company’s name, address, contact information, and identification number.
3. Customer’s Business Information:
   Similarly, as in the previous step, you’ll want to include your customer’s company’s name, address, contact information, and identification number.
   Furthermore, depending on the customer, you may need to include a TIN (tax identification number). This is particularly relevant for non-profit and child-care service industries.
4. Issue & Delivery & Due Date:
   Each invoice must include when it was issued and delivered for legal and taxation purposes.
5. List of Services or Products Delivered: To help your customers rest easy knowing that you’re not scamming them, you should include a list of all products or services provided, their amount, price per unit, and total price per item. You can also add a description underneath each item to make the invoice (and price) as clear as possible.
6. Total Price:
   Your invoice should include the total price at the bottom of the page and any taxes or extra costs the customer needs to pay.

How to make an invoice in 8 steps

To make an invoice, gather your business and client details, assign a unique invoice number, set the issue and due dates, list itemised services or products, calculate subtotal and tax, state payment terms and methods, save the file as a PDF, and send it the same day the work is delivered.

The same eight steps apply whether you’re using a template, a generator, or full invoicing software. The difference is how much each tool automates. For ongoing invoicing across multiple clients, automatic payment reminders take the chase-for-payment work off your plate.

Step 1 — Start from a generator (don’t build from scratch)

Creating an invoice from scratch in Word wastes time and introduces errors. Use Billdu’s free invoice generator to skip the layout work entirely — it pre-fills the structure, auto-numbers the invoice, calculates totals, and exports a clean PDF. Pick a format once — the same one for every invoice — and stick with it.

Step 2 — Add your business details

Your full business name, trading name, address, email, phone, and (if applicable) VAT or tax registration number. This block goes in the header, typically top-left. Upload your logo if you have one — branded invoices signal professionalism and are paid on average 5% faster than unbranded ones.

Step 3 — Add the client’s details

The client’s legal business name, billing address, accounts-payable contact person, and their email. Verify this block with a new client before sending the first invoice — wrong details here are the #1 reason invoices get returned from AP departments.

Step 4 — Assign a unique invoice number

Use the format you committed to in Step 1. Most small businesses start at INV-2026-0001 and increment by one. For the six numbering formats and rules — including the UK/EU requirement for unbroken sequential numbering — see the dedicated guide. Invoicing software handles this automatically.

Step 5 — Set the issue date and due date

The issue date is today. The due date follows your payment terms (Net 15, Net 30, or a specific calendar date). Net 30 is the default for most B2B work; Net 15 is common for freelance. Write the due date as a specific date (“Due: 15 May 2026”), not as a number of days — specific dates produce faster payment.

Step 6 — List itemised line items and calculate the total

One row per product or service. For each: specific description, quantity or hours, unit price, line total. Below the items: subtotal, tax as a separate line (even if 0%), and grand total in bold. Let the invoicing tool calculate — manual maths in Word is where errors happen. If you invoice the same client on a recurring basis, set this up once with recurring invoices and the tool handles every future one.

Step 7 — State payment terms and methods

Add the payment-terms block: number of days, early-payment discount (if any), late-payment fee (if any), and every accepted payment method with the details needed to pay. If you accept online payments, include the direct payment link here — it’s the single biggest lever for getting paid faster.

Step 8 — Save as PDF and send

Save the final invoice as a PDF (not Word or Excel — clients may not be able to open editable formats, and editable invoices can be altered). Send it the same day the work is delivered. Then use invoice tracking to confirm the client opened it, and set a payment reminder for three days before the due date.

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5 ways to make an invoice (comparison)

The five main ways to make an invoice are Microsoft Word, Microsoft Excel or Google Sheets, a free online invoice generator, dedicated invoicing software, and fully manual design — each with different trade-offs in speed, cost, and professionalism.

Choose based on how many invoices you send per month and how much automation you need. The comparison table below summarises the trade-offs — all five methods produce a compliant invoice, but time cost and professionalism vary significantly.

When each option makes sense

For one-off or very occasional invoicing, a free online generator is the fastest path — fill in the fields, download the PDF, send. For businesses sending more than five invoices a month, dedicated invoicing software pays back the subscription cost in the first week through saved time and avoided reconciliation errors.

If you prefer working in Microsoft Office, the dedicated guides for how to make an invoice in Word and how to make an invoice in Excel walk through both step-by-step.

How to send an invoice to your client

Send your invoice as a PDF attachment to the client’s accounts-payable email on the same day the work is delivered, including the invoice number, total due, and due date in the email subject line so the key information is visible without opening the attachment.

Send the PDF the same day the work is delivered — every day you wait adds days to the payment timeline. Attach it to an email addressed to the accounts-payable contact you verified in Step 3, with a subject line like:

Subject: Invoice INV-2026-0142 — $2,400 — Due 15 May 2026

Include a brief one-line body message and a clickable payment link if available. For the full playbook on invoice delivery, timing, and follow-up, see our guide on how to send an invoice.

How long does it take to get paid?

B2B payment cycles average 62 days from invoice issue to payment globally according to the Atradius 2025 Payment Practices Barometer, and the gap between prompt payers and late payers has widened year-on-year since 2023.

Payment speed is one of the few operating metrics that compounds — faster payment means better cash flow, which means you can take on bigger contracts without taking on debt. Three factors drive the largest gap between slow and fast payers, and all three are within the control of the business issuing the invoice.

1. Payment method

Invoices paid online (card or direct payment link) clear faster than bank transfer because there’s no back-and-forth on account details, and the client doesn’t have to leave their inbox. Adding a one-click payment link is the single highest-leverage change to invoice design that does not require renegotiating terms with the client.

2. Automatic payment reminders

Businesses using automated reminders see materially shorter payment cycles than businesses that follow up manually — reminders catch invoices that have been genuinely forgotten in a busy AP queue. The Atradius data shows that even one polite reminder three days before the due date measurably reduces overdue rates.

3. Send-day discipline

Invoices sent the same day the work is delivered get paid faster than invoices sent a week later, even when the due date is identical. The client’s payment decision is made against their current cash cycle, not yours — being present in their queue when they’re allocating that cycle’s payments matters more than the calendar due date you printed on the document.

Industry benchmark for contrast: the Atradius 2025 Payment Practices Barometer reports an average 62 days from invoice issue to payment across B2B transactions globally, with the delta between prompt and late payers widening year-on-year since 2023.

Legal requirements by country

Invoice-creation rules are set by each country’s tax authority: the US IRS requires adequate records without a mandated format, UK HMRC requires sequential VAT-invoice numbering, the Australian ATO requires a unique identifier and the words ‘Tax invoice’, and the EU VAT Directive requires sequential numbering with uniqueness.

Below is a summary of the four jurisdictions most relevant to Billdu’s markets. Always verify current rules with your local tax authority — these requirements change.

United States — IRS

The IRS does not mandate a specific invoice format but requires businesses to maintain adequate records substantiating all income and deductions, typically for at least 3 years.

US federal law does not prescribe an invoice template. What the IRS does require, through Publication 334 and Publication 583, is “permanent, accurate, and complete records” of business income and deductions. Practical implications:

• Every invoice must have a unique identifier so income can be traced to a specific transaction
• Sequential numbering is not legally required but is the universal convention in US accounting software
• Keep records at least 3 years; up to 7 years in certain situations (claims for losses, bad debts)
• Electronic invoices are fully accepted as long as they are legible, accessible, and accurately reproduce the original
• Sales tax rules are state-level — check your state’s Department of Revenue for the specific requirement

Primary sources: IRS Publication 334 (Tax Guide for Small Business); IRS Publication 583 (Starting a Business and Keeping Records).

United Kingdom — HMRC

HMRC requires VAT-registered UK businesses to issue invoices with a unique, sequential identification number and to issue VAT invoices within 30 days of the supply of goods or services.

For VAT-registered UK businesses, invoice format is specified in VAT Notice 700/21. The invoice number must be part of a continuous, gap-free sequence. HMRC inspectors check this first during a VAT inspection:

• Full VAT invoices must have a unique, sequential number with no gaps
• Separate invoice sequences per client are allowed as long as each sequence is itself complete
• VAT invoices must be issued within 30 days of the supply
• Records including invoices must be kept for at least 6 years
• Credit notes must use a separate numbering sequence
• Making Tax Digital — VAT records must be compatible with HMRC-approved digital software

Primary sources: GOV.UK — Invoicing and taking payment from customers; HMRC VAT Notice 700/21 (Keeping VAT records).

Australia — ATO

The Australian Taxation Office requires every tax invoice to carry a unique identifier and the words ‘Tax invoice’ for GST-registered sellers, with the ABN shown prominently.

GST-registered Australian businesses must issue a tax invoice within 28 days of a customer request for any taxable sale of AUD 82.50 or more (including GST). The ATO’s requirements are in GSTR 2013/1:

• Every tax invoice must be uniquely identifiable with an invoice number
• The words “Tax invoice” must appear prominently
• The seller’s ABN must be shown
• For sales of AUD 1,000 or more, the buyer’s identity or ABN must also be shown
• Records must be kept for at least 5 years
• Australia has adopted the Peppol framework for e-invoicing between businesses

Primary sources: ATO — Tax invoices; GSTR 2013/1 (Goods and services tax: tax invoices); business.gov.au — How to invoice.

European Union — VAT Directive

Article 226 of the EU VAT Directive requires every VAT invoice issued in a member state to include a sequential number, based on one or more series, that uniquely identifies the invoice.

Under Council Directive 2006/112/EC, every VAT invoice issued in an EU member state must contain “a sequential number, based on one or more series, which uniquely identifies the invoice.” Member states may add requirements on top — Germany’s GoBD rules, for example, require the numbering system to be tamper-proof and auditable. Cross-border B2B invoicing across the EU is increasingly governed by Peppol-compliant electronic invoice formats:

• Invoice numbers must be sequential and unique
• Multiple parallel series are allowed if each is internally complete
• Most member states require invoices to be kept for 6–10 years
• E-invoicing is being phased in across EU member states through 2026 and beyond — check local rules

Primary source: Council Directive 2006/112/EC on the common system of value added tax (the EU VAT Directive).

Common invoice-creation mistakes to avoid

The six most common mistakes small businesses make when creating an invoice are vague line-item descriptions, missing or non-unique invoice numbers, using ‘Net 30’ instead of a specific due date, forgetting VAT or tax information, wrong client billing details, and sending the invoice days after the work is delivered.

Each of these errors is responsible for a disproportionate share of delayed and disputed payments. All are easy to avoid if flagged upfront.

Vague line-item descriptions

“Consulting — $2,500” invites an accounts-payable team to reject or query the invoice. “Brand strategy workshop, 4 hrs @ $625/hr — $2,500” is approved on first pass. Specificity does not just help the client pay faster; it also protects you in a dispute.

Missing or duplicate invoice numbers

Every invoice must carry a unique number, and that number must never be reused — even across tax years. In the UK and EU this is a legal requirement; in the US and Australia it is the audit standard. Use invoicing software to handle numbering automatically and avoid the whole class of error.

“Net 30” instead of a specific due date

“Net 30” is ambiguous — 30 days from issue, from delivery, from receipt? “Due: 15 May 2026” leaves no room for interpretation and creates visible urgency the client’s AP system will act on.

Forgetting VAT, GST, or sales tax

If you are VAT- or GST-registered, the registration number and the tax amount must be on every invoice. Missing this is the single biggest reason UK and Australian invoices get returned. Even if the tax rate is 0%, show the line — it demonstrates that you checked.

Wrong client billing details

Sending the invoice to the day-to-day project contact rather than the accounts-payable contact is how invoices disappear into inbox black holes. Confirm the AP contact and billing address with every new client before you send the first invoice — not when you’re chasing payment.

Sending the invoice days after the work is delivered

Invoice timing is one of the strongest predictors of payment speed. An invoice sent the same day the work is delivered gets paid on average a week faster than one sent five days later. The client’s decision is made against their current cash cycle, so being in their queue matters more than when the due date is set.

For more patterns that trip up invoice creators, see our guide to common invoicing mistakes.

Methodology and sources

This guide is based on primary tax-authority documentation from the IRS, HMRC, ATO, and the EU VAT Directive, combined with industry benchmark data from the Atradius 2025 Payment Practices Barometer.

Legal requirements were verified against primary government sources in April 2026. Industry comparison data uses the Atradius 2025 Payment Practices Barometer (publicly published industry benchmark, not a Billdu product). Every statistic is dated; every legal claim links to a primary source.

Primary sources consulted:

•       IRS Publication 334 — Tax Guide for Small Business
•       IRS Publication 583 — Starting a Business and Keeping Records
•       GOV.UK — Invoicing and taking payment from customers
•       HMRC VAT Notice 700/21 — Keeping VAT records
•       Australian Taxation Office — Tax invoices (GSTR 2013/1)
•       business.gov.au — How to invoice
•       Council Directive 2006/112/EC — EU VAT Directive
•       Atradius Payment Practices Barometer 2025

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