How to Write an Invoice: A Step-by-Step Guide

Writing an invoice is simple once you know the eight parts every client's accounts-payable team expects. Miss one and your bill gets stuck in a queue; include them all and you get paid without a single follow-up. Here's the exact process — grab the free invoice template to follow along.

1. Label it clearly as an invoice

Put the word Invoice at the top. It sounds obvious, but AP systems and inboxes triage on it. Add your logo if you have one — it signals a real business.

2. Add a unique invoice number

Every invoice needs a unique, sequential number (e.g. INV-0007). This is how both you and your client track payment. Never reuse a number, and never leave it blank.

3. Include your details and the client's

List your business name, address and contact email, then the client's company, the specific person or department (often "Accounts Payable"), and their email. If they use purchase orders, add the PO number — many enterprises won't pay without it.

4. Add issue and due dates

Show the issue date and an explicit due date. Don't rely on "due on receipt" alone — write the calendar date and the terms, e.g. Due 2026-07-31 (Net 30).

5. Itemize the work

This is where most invoices go wrong. List one deliverable per line with a clear description, quantity and unit price. A single "Services rendered — $3,000" line is the number-one reason invoices get questioned. Specificity gets you paid.

6. Show subtotal, tax and total

Add a subtotal, then any tax on its own line with the rate shown, then the grand total. Never bake tax into your unit prices — B2B expense audits will flag it. (When and whether to charge tax depends on your jurisdiction; check local rules.)

7. State payment terms and methods

Spell out how and when to pay: accepted methods, bank/ACH details or a pay link, and the terms. Shorter terms (Net 7–14) get you paid faster than the default Net 30.

8. Send it and follow up

Send the invoice as a PDF so the numbers can't be altered, keep a copy for your records, and send a friendly reminder a few days before the due date.

Ready to write yours? Start from the free invoice template — or if you want totals to calculate automatically, use the Excel version. Freelancers billing hourly should grab the freelance invoice template.