How to Write an Invoice

Have three things in front of you: what you agreed with the client (a quote, an email or a contract), a note of the work you actually did, and the client's billing details. If the client is a company, ask who handles payments. The person who hired you is often not the person who pays you. Not sure whether you need an invoice, a quote or a receipt? See invoice vs. receipt vs. quote.

1. Title it “Invoice.” It sounds obvious, but it tells the client's bookkeeper exactly what kind of document this is.
2. Give it a unique number. A simple sequence such as 1001, 1002, 1003 works. Never reuse a number, even for a different client.
3. Add your details: business name, address, email and phone. If you work under your own name, use that.
4. Add who you're billing: the client's name or company, their billing address, and a contact person if they gave you one.
5. Date it. Use the day you send it. That's the date payment terms count from.
6. Set the due date. Write a real date, or terms such as Net 15 or Net 30 with the date beside it. See invoice payment terms.
7. List the work. One line per service or product, each with a short description, a quantity (hours, units, days) and a rate. The amount is quantity times rate.
8. Add it up. Subtotal, then any discount, then sales tax if you charge it, then the total due in bold.
9. Say how to pay. Bank transfer (ACH), card, check, Zelle, PayPal: list what you accept and the details the client needs.

Notice what each line does: a client can read it months later and still know what they paid for. Vague lines like “Services rendered” are the ones that get questioned and paid late.

• Send a PDF, not an editable file. It looks the same on every screen and can't be changed by accident.
• Put the invoice number and amount in the email subject, for example “Invoice 1042, $1,590.00, due April 2.”
• Send it the day the work is done or the milestone is reached. Every day you wait pushes the due date back too.
• Keep a copy. The IRS generally expects you to keep records that support your income for at least three years, and longer in some cases.

Send a friendly reminder a few days before the due date, another on the day, and a firmer one a week after. Each time, attach the invoice again and repeat the amount and how to pay. If your agreement allows it, a late fee can follow; see late fees on invoices.