How to Write an Invoice: A Step-by-Step Guide
Every field an invoice needs — business details, line items, taxes, payment terms — explained with a worked example.
Writing your first invoice is simpler than it looks. An invoice is just a formal request for payment, and it needs to answer five questions: who is billing, who is being billed, what for, how much, and when it's due. Here's how to cover each one.
Add your business details
Your business name, address, phone, and email go at the top, along with your logo if you have one. If you're registered for VAT or have a tax number, include it.
Add the client's details
The client's name (and company name if applicable), billing address, and contact details. Double-check the spelling — this is who the bill is legally addressed to.
Number and date the invoice
Give the invoice a unique number (for example INV-2026-0001) and the invoice date. Add a due date or payment terms like 'Net 14'.
List what you're billing for
Each line item needs a clear description, quantity, and unit price. '12 hours of web development at $80/hr' beats 'services rendered'.
Add taxes, discounts, and shipping
Apply any discounts first, then your tax rate on the discounted subtotal, then shipping. The total is what the client owes.
Say how to pay
Include payment instructions — bank details, a payment link, or a reference the client should use. Add notes or terms if needed.
Common mistakes to avoid
- Vague line items the client can't recognize.
- No due date — without one, 'when is it due?' is a negotiation.
- Missing payment details, forcing the client to ask how to pay you.
- Reusing invoice numbers or skipping them without a record.