How to write an invoice

What to include on an invoice

Most invoices, in most countries, carry the same core details:

• The word “Invoice” at the top, so it isn’t mistaken for a quote or a receipt.
• A unique invoice number and the invoice date.
• Your details: name or business name, address, email or phone, and your tax or registration number if you have one.
• Your client’s details: their name or company and address.
• What you’re charging for: a clear description of each product or service, the quantity (hours, days, pieces) and the rate.
• Totals: the subtotal, any discount, each tax with its rate, shipping if any, and the total due.
• When and how to pay: the due date or payment terms and your payment details (bank account, IBAN and SWIFT, or a payment link).

Optional extras that help: a purchase order (PO) number if your client uses them, a short thank-you note, and your terms (late fees, ownership of work until paid).

Writing an invoice, step by step

1. Choose a template. A clean layout with your logo looks professional and makes the total easy to find. In the invoice generator, pick one of ten designs and your brand colour.
2. Add your business details. They stay the same on every invoice, so the generator keeps them for the next one.
3. Add the client exactly as they want to be billed. Big companies often need their registered name and a PO number.
4. Give it a number and a date. Use the next number in your series (see below).
5. List the work. One line per product or service. Describe it in words your client’s accounts team will recognise: “Website redesign, phase 2” beats “Work”.
6. Add discount, tax and shipping if they apply. The generator works out the totals.
7. Set the terms: a due date or “Net 30”, and how to pay.
8. Check the preview and download the PDF. Send it to the right person: often accounts payable, not your day-to-day contact.

How to number invoices

Every invoice needs a number you never reuse, so you and your client can refer to it and your records add up. Simple patterns work best:

• Sequential: INV-0001, INV-0002, INV-0003 …
• By year: 2026-001, 2026-002 … starting again each year.
• By client: ACME-001, ACME-002 … if you have a few large clients.

Don’t skip or repeat numbers. In the generator, “New” starts the next invoice with the next number filled in. Some countries have their own numbering rules: in India, GST invoice numbers must be consecutive and at most 16 characters (the GST invoice format guide explains them).

More formats, yearly series and what to do about gaps: invoice number format.

Payment terms

Payment terms tell your client when payment is due. The common ones:

• Due on receipt: pay as soon as the invoice arrives.
• Net 7, Net 15, Net 30: pay within 7, 15 or 30 days of the invoice date. Type “Net 30” in the generator and the due date is filled in for you.
• Deposit or milestones: for example 50% upfront and 50% on delivery. Send a proforma invoice or an invoice for each part.

If you charge late fees or interest, say so in your terms, and check what the law allows where you and your client are. The guide to payment terms has example due dates and wording.

Tax on invoices

Whether you add tax depends on where you are and whether you are registered for it: VAT in the UK and Europe, GST in Australia, New Zealand, Singapore and India, sales tax in the US, GST/HST in Canada. If you are registered, local rules usually require extra details such as your tax number, the tax rate and amount, and sometimes the words “Tax invoice”. Check your tax authority’s guidance or ask an accountant.

The invoice generator lets you add up to two taxes with your own names and rates. In India, a GST-registered business issues a GST tax invoice. Use the GST invoice generator, which adds GSTINs, the place of supply and CGST + SGST or IGST.

Invoice, quote, proforma or receipt?

• Quote or estimate: the price before the work starts, with a “valid until” date.
• Proforma invoice: the expected bill before delivery, often to get approval or an advance. Make a proforma invoice.
• Invoice: the request for payment once the work is done or the goods are delivered.
• Receipt: confirmation that you were paid. Make a receipt.

Mistakes that delay payment

• Sending it to the wrong person, or without the client’s PO number.
• Vague descriptions the client can’t match to the work.
• No due date, or no payment details.
• Arithmetic errors: let the generator do the totals.
• Waiting weeks to invoice. Send it as soon as the work is delivered.