How to write an invoice: what to include, with an example

An invoice is the document that asks a customer to pay for goods or services you have already delivered. A clear invoice gets paid faster, keeps your accounts in order and protects you if there is ever a dispute. This guide walks through every part of an invoice and the mistakes that most often delay payment.

What an invoice must contain

The exact rules depend on your country, but almost every invoice in the world includes the same core details:

• The word "Invoice" at the top, so nobody confuses it with a quote or a receipt.
• A unique invoice number that follows a continuous sequence.
• The issue date and, if you give credit, the due date.
• Your details: business name, address, contact information and, where required, your tax or registration number.
• Your customer's details: name, address and, for business customers, their tax number if your rules require it.
• A line for each product or service with a clear description, quantity, unit price and line total.
• Subtotal, taxes and total, with the tax rate shown for each line or group of lines.
• Payment details: how and where to pay, such as bank account, IBAN or mobile payment.

Atlas Studio12 Harbour Street
Casablanca 20250[email protected]

Invoice

Number

INV-0042

Date

Mar 14, 2026

Due date

Apr 13, 2026

Bill to

Northwind Trading48 Rue de Lyon
75012 Paris

Ship to

Northwind Warehouse9 Quai de Bercy
75012 Paris

Description	Qty	Unit price	Amount
Brand identity design	1	$1,800.00	$1,800.00
Website pages (5)	5	$320.00	$1,600.00
Product photography, half day	1	$650.00	$650.00
Print-ready files	1	$150.00	$150.00

Notes

Thank you for your business.

Subtotal	$4,200.00
Tax 20%	$840.00
Total	$5,040.00

How to number your invoices

Use a simple, continuous sequence and never reuse a number, even if you cancel an invoice. Common formats are:

If you make a mistake on an invoice that was already sent, do not edit or delete it. Issue a credit note that cancels it, then send a new invoice.

Payment terms that get you paid

Payment terms tell the customer when the money is due. Write them as a date, not only as a phrase: "Due date: 15 November 2026" is clearer than "Net 30".

• Due on receipt: for small amounts and new customers.
• Net 15 or Net 30: the most common terms between businesses.
• Deposit + balance: ask for 30% to 50% up front on large projects and state the remaining balance on the final invoice.

If you received a deposit, show it as "Amount paid" so the invoice clearly displays the balance due.

Taxes and discounts

Show each tax rate separately. If some items are taxed at different rates, or not taxed at all, the total tax should be split by rate. Apply discounts before tax unless your local rules say otherwise, and label them clearly, for example "Discount (10%)".

If your prices already include tax, as is common in retail, say so on the invoice and show the tax included in the total. A good generator handles both cases.

Common mistakes that delay payment

1. Missing or wrong customer details, so the invoice cannot be approved by their accounts team.
2. Vague descriptions such as "Services". Write what you did and for which period.
3. No due date, or a due date that is not visible.
4. Missing bank details, or details in an image that cannot be copied.
5. Sending an editable file instead of a PDF. Always send a PDF and keep a copy.

Write your invoice in a few minutes

Fill in your details once and save them as default. Next time, only the customer and the items change. When the job started from a quote, you can convert the quote into an invoice in one click, and after payment turn the invoice into a receipt.