How to Write an Invoice: Step by Step
An invoice is a request for payment that also serves as a record for you and your client's bookkeeping. A clear invoice gets paid faster and avoids questions.
1. Use a unique, sequential invoice number
Number invoices in one continuous sequence (for example INV-2026-001, INV-2026-002). In the EU a sequential number is a legal requirement for VAT invoices, and it helps you track payments everywhere.
2. Add your details and your client's
Include your name or business name, address and contact details, plus your client's full name and address. If you are VAT registered, add your VAT number; for EU B2B work add the client's VAT number too.
3. Set the issue date and due date
State when the invoice was issued and when payment is due. Common terms are 14 or 30 days. Writing an actual date ("due 31 Oct 2026") is clearer than "net 30".
4. List what you delivered
Describe each product or service on its own line with quantity, unit price and line total. Specific descriptions ("Logo design, 3 concepts") prevent disputes.
5. Show subtotal, tax and total
Show the amount before tax, the tax rate and amount, and the total due, all in one clearly stated currency.
6. Explain how to pay
Add bank details (IBAN/BIC) or another payment method, and any notes such as late-payment terms.
7. Send it as a PDF and keep a copy
PDFs look the same on every device and can't easily be edited. Keep copies for your records; many countries require you to retain invoices for several years.