Guides · 2026-10-12

How to Write an Invoice (Step-by-Step, With Example)

An invoice has one job: make it easy for your client to pay you the right amount, on time, without having to email you a question first. Every section below exists to remove a reason for delay. Follow the steps in order and you will end up with a professional invoice you can send today.

What every invoice needs

Before the step-by-step, here is the short checklist. If any of these are missing, expect a follow-up email from your client's accounts team.

• The word Invoice clearly at the top
• A unique invoice number
• Invoice date and due date
• Your name or business name, address, and contact details
• Your client's name, business name, and billing address
• An itemized list of what you are charging for
• Subtotal, any tax, and the total amount due
• Payment terms and how to pay

Step 1: Add your business details

Put your name or trading name, business address, email, and phone number at the top. If you are registered for sales tax, VAT, or GST, include your registration number here. Some jurisdictions require certain details (for example, a VAT number on VAT invoices in the UK, or an ABN on Australian tax invoices), so check local rules if you are unsure what applies to you.

A logo is optional. It helps your invoice look established, but a clean text header works just as well.

Step 2: Add your client's details

Use the client's legal business name and billing address, not just the name of the person you worked with. Larger companies often route invoices through an accounts payable team, so add a contact name or department if you have one:

Bill to: Northwind Design Ltd, Attn: Accounts Payable, 42 Harbour Street, Bristol BS1 4XX

If the client gave you a purchase order (PO) number, include it. Invoices without a required PO number are one of the most common reasons payments get stuck.

Step 3: Number and date the invoice

Give every invoice a unique, sequential number. It helps you track payments and is expected by tax authorities in many countries. Simple formats work best:

• Sequential: 0001, 0002, 0003
• Year-based: 2026-001, 2026-002
• Client-based: NWD-001, NWD-002

Never reuse a number, even if you cancel an invoice. Instead, issue a credit note or mark the old one as void and start a new number.

Add two dates: the invoice date (the day you issue it) and the due date (the day payment is expected). Writing an actual date, such as 11 November 2026, is clearer than only writing Net 30.

Step 4: List your products or services

This is where most invoice confusion starts. Each line item should tell the client exactly what they are paying for, without needing to dig through old emails. Include a short description, the quantity or hours, the rate, and the line total.

Compare these two descriptions:

• Vague: Design work - $1,200
• Clear: Homepage redesign, 2 rounds of revisions (as per proposal dated 3 Sept) - 16 hours at $75/hr - $1,200

The second one answers the questions an approver will ask before they ever get to you.

Step 5: Calculate subtotal, tax, and total

Add up the line items to get your subtotal. Then apply any discount, then any sales tax, VAT, or GST that applies to you, and show the tax as its own line. Finally, show the total amount due in bold or larger text so it cannot be missed.

Tax rules vary widely. Whether you must charge tax, at what rate, and what has to appear on the invoice depends on where you and your client are based and whether you are registered. Check with your local tax authority or an accountant if you are not sure.

Step 6: State payment terms and how to pay

Tell the client when to pay and exactly how. Here is wording you can copy:

Payment terms: Net 14. Please pay by 26 October 2026.

Pay by bank transfer to: Jane Smith, Account 12345678, Sort code 00-00-00. Please use invoice number 2026-014 as the payment reference.

If you accept cards or online payments, add the link. The fewer steps between reading the invoice and paying it, the better. For more on choosing terms, see our guide to invoice payment terms.

Step 7: Add a short note

A one-line note at the bottom is a small touch that clients notice. For example: Thank you for your business. Questions about this invoice? Email jane@example.com. If you charge late fees, state them here too, and make sure they were agreed in your contract and allowed under local rules.

Invoice example

Here is a complete example for a freelance web designer. Use it as a model for your own.

• INVOICE #2026-014
• Invoice date: 12 October 2026
• Due date: 26 October 2026 (Net 14)
• PO number: NWD-PO-8841

From: Jane Smith Design, 10 Market Lane, Bath BA1 1AA, jane@example.com

Bill to: Northwind Design Ltd, Attn: Accounts Payable, 42 Harbour Street, Bristol BS1 4XX

Payment: Bank transfer to Jane Smith, Account 12345678, Sort code 00-00-00. Reference: 2026-014.

Note: Thank you for your business.

Rather than building this by hand in a word processor, you can fill in the same fields in our free invoice maker and download a PDF in a couple of minutes.

Common mistakes that delay payment

• Missing PO number. Many companies will not process an invoice without one.
• Wrong billing entity. Invoicing the person instead of the company can send your invoice back to the start of the queue.
• No due date. Without one, your invoice may simply be paid whenever is convenient.
• Vague line items. If an approver cannot tell what something is, they will ask, and the clock stops.
• Math errors. Double-check totals, or use a tool that calculates them for you.
• Hard-to-find payment details. Put bank details or a payment link near the total.

How to send your invoice

Send the invoice as a PDF so formatting cannot change and it cannot be accidentally edited. Use a clear email subject line and a short message:

Subject: Invoice 2026-014 from Jane Smith Design - due 26 Oct

Hi Sam, please find attached invoice 2026-014 for the homepage redesign, totalling 1,560.00 and due on 26 October. Payment details are on the invoice. Let me know if you need anything else to process it. Thanks, Jane

Send it as soon as the work is delivered, while the value is fresh in the client's mind. Keep a copy, note the due date in your calendar, and if the date passes, follow up politely. Our late payment email templates give you ready-made wording for that.

Start from a template

Once you have written one good invoice, reuse the layout every time so clients learn where to find the information they need. Browse our invoice templates to pick a design for your trade, then fill it in and send it.

Create a free invoice now →