How to Write an Invoice: What to Include, Step by Step

To write an invoice, put your business name and contact details at the top, add the buyer's details, give the invoice a unique number and a date, list each item with its quantity, unit price and line total, then add tax, the grand total, the currency and your payment terms with how to pay. Send it as a PDF and keep a copy. That is the whole job; the rest of this guide shows each part in detail, a filled example, and the mistakes that delay payment.

What is an invoice?

An invoice is a document a seller sends to a buyer asking for payment for goods or services already supplied or agreed. It records what was sold, at what price and on what terms, so it is also the buyer's proof of purchase and your record for tax and accounts.

There are a few related documents that people mix up:

Document	When it is used	Asks for payment?
Quotation	Before the order, to offer a price	No
Purchase order	Sent by the buyer to confirm the order	No
Proforma invoice	Before shipment, for advance payment or an import licence	Sometimes, as an advance
Invoice / commercial invoice	After supply or at shipment	Yes

If you are unsure which one you need, our guides on purchase order vs invoice and proforma vs commercial invoice explain the difference.

What to include on an invoice

Every invoice should include these details, whatever you sell:

1. The word "Invoice" at the top, so nobody mistakes it for a quote.
2. Your details: business name, address, phone or email, and your tax or registration number if you have one.
3. The buyer's details: company name, contact person and address.
4. Invoice number: unique and in sequence, such as INV-2026-0042. Never reuse a number.
5. Invoice date and, if different, the date of supply.
6. Item lines: a clear description, quantity, unit (pcs, kg, boxes), unit price and line total.
7. Subtotal, tax and total, with the tax rate shown if tax applies.
8. Currency, written as a code (USD, EUR, AED) when you trade across borders.
9. Payment terms: the due date or terms such as "30 days from invoice date".
10. How to pay: bank details or a payment link.

Tax rules decide some extra fields, such as a tax number for the buyer or wording for exempt sales. They differ by country, so check what your tax office requires. For India, see our GST invoice format.

How to write an invoice step by step

Follow these steps in order and you will not miss a field.

1. Choose a template or generator. A blank word processor works, but a template keeps the layout and totals right.
2. Add your header: logo, business name, address and contact details.
3. Add the buyer: use their registered company name, not a nickname.
4. Number and date it: take the next number in your sequence.
5. List the items: one line per product or service, with quantity, unit and unit price. Write descriptions a stranger could understand: "Porcelain floor tile 60x60 cm, matt grey" beats "tiles".
6. Total it: subtotal, discount if any, tax, shipping if charged, and the grand total.
7. Write the payment terms and how to pay.
8. Check it against the order or purchase order: same quantities, same prices, same buyer name.
9. Save as PDF and send, with the invoice number in the email subject.

Invoice example

Here is what the item section and totals of a simple goods invoice look like:

Description	Qty	Unit	Unit price (USD)	Total (USD)
Porcelain floor tile 60x60 cm, matt grey	1,200	boxes	8.40	10,080.00
Skirting tile 60x8 cm, matt grey	300	boxes	2.10	630.00
			Subtotal	10,710.00
			Total due	USD 10,710.00

Below the table: "Payment terms: 30% advance, 70% against copy of bill of lading. Pay by bank transfer to [bank details]."

How to write an invoice for goods sold abroad

When goods cross a border, the invoice is usually called a commercial invoice and customs at the destination reads it to work out duty. Add these fields on top of the basics:

• Incoterm and place, such as FOB Karachi or CIF Valencia, so it is clear who pays freight and insurance. See our Incoterms guide.
• Country of origin of the goods.
• HS code for each item, if you know it.
• Ports of loading and discharge, and the shipping marks if used.
• Gross and net weight and the number of packages.

The values must match the packing list, the bill of lading and any letter of credit exactly. A mismatch is the most common reason a bank or customs office holds a shipment.

Make an invoice from one sentence

The fastest way is our free AI invoice generator. Describe the order in plain words, for example "Indus Tiles, Karachi sells to Casa Ceramica, Valencia: 1,200 boxes of porcelain tile at $8.40 per box, FOB Karachi, 30% advance", and choose a proforma invoice, commercial invoice or purchase order. It shows what it understood (seller, buyer, items, prices, terms) so you can check it, then opens the full form already filled in. You edit anything, add your logo, and download it. Anything you did not mention stays empty; it does not guess.

Prefer to fill the form yourself? Use the commercial invoice generator or the proforma invoice generator. Both are free with no sign up.

Common invoice mistakes that delay payment

Most late payments start with a small error on the invoice. Avoid these:

• No due date. "Payable on receipt" or a real date gets paid sooner than nothing.
• Wrong buyer name. Large companies route invoices by legal name; a trade name can get it lost.
• Missing purchase order number when the buyer issued one. Many accounts teams cannot pay without it.
• Duplicate invoice numbers, which confuse both sides' records.
• Totals that do not add up. Recalculate after every change, or use a tool that does it.
• No bank details. Put them on the invoice, not only in a separate email.

Frequently asked questions

What are the basic things to put on an invoice?

Your business name and contact details, the buyer's details, a unique invoice number, the date, each item with quantity, unit price and total, tax if it applies, the grand total with currency, and your payment terms and bank details.

Can I write an invoice without a company?

Yes. Freelancers and sole traders can invoice under their own name. Use your full name and address as the seller, and add a tax number if your country requires one for your income or sales.

How do I number my invoices?

Use a simple sequence that never repeats, such as INV-2026-0001, INV-2026-0002. Adding the year helps you sort them. Do not skip or reuse numbers, because tax offices and buyers use them to track payments.

What is the difference between an invoice and a receipt?

An invoice asks for payment; a receipt confirms payment was made. You send the invoice first and issue a receipt, or mark the invoice paid, once the money arrives.

Is there a free way to create an invoice?

Yes. TradingForms has free proforma invoice, commercial invoice and purchase order generators with no sign up, and an AI invoice generator that fills the form from one sentence. You can download the result and edit every field.