How to write an invoice

A step-by-step guide for freelancers and small businesses, from the header to the payment details.

An invoice is a request for payment: it tells your customer what they bought, how much they owe and how to pay. Writing one takes a few minutes once you know what goes where. Here’s the order to fill it in.

1. Add your business details and logo

Put your business name, address, email and phone number at the top. If you have a logo, add it – a branded invoice looks more professional and is easier for the customer to recognise in a pile of paperwork. If you are registered for a sales tax such as GST or VAT, add your registration number here too.

2. Title it and give it a unique number

Write “Invoice” clearly at the top, or “Tax Invoice” if your tax rules require it. Then give it an invoice number. Each number must be unique and they should run in sequence, such as INV-001, INV-002, INV-003. A prefix with the year (2026-001) also works. Never reuse a number, even for a cancelled invoice – issue a credit note instead.

3. Add your customer’s details

Under “Bill to”, enter the name of the person or company paying, with their billing address. For business customers, use the company’s legal name and add their tax number if your country requires it. If the goods go somewhere else, add a separate “Ship to” address.

4. Set the invoice date and due date

The invoice date is the day you issue it. The due date is when payment must arrive. State the payment terms in words as well, for example “Due in 14 days” or “Net 30” (payment within 30 days of the invoice date). A specific date gets paid faster than “due on receipt”. If the customer gave you a purchase order (P.O.) number, add it – many accounts teams cannot pay an invoice without one.

5. List what you are charging for

Add one line for each product or service, with:

• a clear description – “Logo design, 3 concepts and 2 revision rounds” rather than “Design work”;
• the quantity (units, hours or days);
• the rate or unit price;
• the line amount (quantity × rate).

Some countries also expect a product or service code on tax invoices, such as HSN/SAC codes in India.

6. Add discounts, tax and shipping

Below the items, show the subtotal, then any discount, then each tax as its own line with its rate (for example “GST 18%” or “Sales Tax 8.25%”), and any shipping charge. If the customer paid a deposit, show it as amount paid so the balance due is unmistakable. Only charge tax if you are registered for it; if you aren’t, leave tax off.

7. Explain how to pay

Tell the customer exactly how to pay you: bank account details, a UPI ID, a card payment link, or the methods you accept. This is the step most often forgotten, and every question the customer has to ask delays payment.

8. Add notes and terms, then send it

Use the notes for a thank-you or job reference, and the terms for things like late-payment fees (where allowed) or warranty conditions. Check the totals, save it as a PDF so the layout can’t change, and send it as soon as the work is done.

Invoice example

A freelance designer billing a client for a website project might write:

• From: Maple & Co. Design, 120 Market Street, San Francisco
• Bill to: Northwind Traders, 500 Oak Avenue, Austin
• Invoice: INV-1042 · dated 13 Oct 2026 · due 28 Oct 2026 (Net 15) · P.O. 7781
• Items: Brand identity design – 1 × $2,400; Website design (5 pages) – 1 × $3,800
• Subtotal $6,200 · Sales tax 8.25% $511.50 · Total due $6,711.50
• Payment: bank transfer to the account shown, quoting INV-1042

Common mistakes to avoid

• Missing or duplicate invoice numbers.
• No due date, or vague terms such as “pay when you can”.
• Vague line descriptions that the customer has to query.
• Forgetting the customer’s P.O. number or tax number.
• Charging tax you aren’t registered for, or leaving out your tax number when you are.
• No payment details.

For the details your country requires, see what should an invoice include? Once it’s sent, these tips for getting paid on time help it turn into money.

Write your invoice now – BillDoodle lays out every section above for you, with your country’s taxes built in.