How to Write an Invoice: Step by Step, With an Example
How to write an invoice in 9 steps: what to include, a complete example invoice, how to write line items and payment terms, how to send it and the mistakes to avoid.
Key Takeaways
- An invoice needs your details, the client's details, a unique number, dates, line items, totals, payment terms and how to pay.
- Write the real due date, not only "Net 15".
- Name each deliverable with a quantity and unit price so the client can check it.
- Send it as a PDF to the person who pays, the day the work is done.
- Some countries require more, such as the supply date in the UK or a TRN in the UAE.
To write an invoice, put your details and your client's at the top, add a unique invoice number, the invoice date and the due date, list what you did with a quantity and price for each line, then show the total, your payment terms and how to pay. Send it as a PDF the day the work is done.
This guide covers one invoice from top to bottom, with a filled-in example. If you want the wider workflow for freelancers, such as when to bill and how to handle late clients, read how to invoice as a freelancer.
How do you write an invoice?
Write an invoice in nine steps:
- Title it "Invoice" so nobody mistakes it for a quote.
- Add your details: your name or business name, address, email and phone, and your tax number if you have one.
- Add your client's details: their name or company, address, and the person or email that pays invoices.
- Give it a unique invoice number, such as INV-2026-001. See how to number invoices.
- Add the dates: the invoice date, the date or period of the work, and the due date.
- List the work: one line per service or product, each with a quantity, a unit price and a line total.
- Add the totals: subtotal, any discount, any tax with its rate, and the total due.
- Add payment terms and details: for example "Net 15" and your bank details or payment link.
- Check it and send it as a PDF, by email, to the person who pays.
What should an invoice include?
An invoice should include enough for the client to check it and pay it without asking you a question.
| Item | Example | Why it matters |
|---|---|---|
| The word "Invoice" | INVOICE | Shows it is a bill, not a quote |
| Your details | Alex Morgan Design, alex@example.com | Tells the client who to pay |
| Client's details | Brightline Software, accounts@example.com | Gets it to the right person |
| Invoice number | INV-2026-014 | Lets both sides track it |
| Invoice date and due date | March 2, 2026 · due March 17, 2026 | Starts the payment clock |
| Description of the work | Website homepage design | Lets the client check it |
| Quantity, unit price, line total | 3 hours × $75 = $225 | Shows how you priced it |
| Subtotal, tax and total | Total due: $3,225.00 | The amount to pay |
| Payment terms | Net 15 | Sets the deadline |
| How to pay | Bank transfer details or a payment link | Removes a reason to delay |
What does a finished invoice look like?
Here is a complete example for a freelance designer.
INVOICE · INV-2026-014
Invoice date: March 2, 2026 · Work done: February 2026 · Due date: March 17, 2026
From: Alex Morgan Design, 12 Elm Street, Portland, alex@example.com
Bill to: Brightline Software, attn. Priya Shah, accounts@example.com
| Description | Qty | Unit price | Amount |
|---|---|---|---|
| Logo design: 3 concepts, 2 rounds of changes | 1 | $1,200.00 | $1,200.00 |
| Website homepage design | 1 | $1,800.00 | $1,800.00 |
| Extra revisions (hours) | 3 | $75.00 | $225.00 |
| Subtotal | $3,225.00 | ||
| Tax | $0.00 | ||
| Total due | $3,225.00 |
Payment terms: Net 15. Pay by bank transfer to [account details]. Thank you for your business.
You can make this invoice in the free invoice generator and download it as a PDF without an account. Or start from a template for your kind of work, such as consulting, hourly work or photography, in the invoice templates.
How do you write line items on an invoice?
Write each line item so the client can recognise the work and check the price: what you did, the quantity and the price per unit.
- Name the deliverable, not just the activity: "Homepage design" is better than "Design work".
- Use the unit you quoted: hours, days, words, pages or a fixed fee (quantity 1).
- Put extras on their own line, such as rush fees, expenses or extra revisions.
- Add dates for hourly or recurring work, for example "Website updates, week of March 9".
What payment terms should you put on an invoice?
Put the term and the real due date, for example "Net 15. Due March 17, 2026". Net 15 suits most freelancers and small businesses; larger companies often ask for net 30. For every option, see the invoice payment terms guide and what net 30 means. To work out a due date, use the due date calculator.
How do you send an invoice?
Send it as a PDF attached to a short email to the person who pays, on the day you finish the work.
Subject: Invoice INV-2026-014 from Alex Morgan Design, due March 17
Body: Hi Priya, please find attached invoice INV-2026-014 for $3,225.00 for the February design work. It is due on March 17, 2026. Payment details are on the invoice. Thanks, Alex.
On the Starter and Pro plans, Due On Time can email the invoice for you, show when the client opens it and add a Pay now button so they can pay by card through your own Stripe account.
Does an invoice need anything else in my country?
Often, yes. In the UK, GOV.UK lists what every invoice must include, such as the supply date and the customer's address (GOV.UK), and VAT-registered businesses must show more. See the UK invoice template. For the UAE, see UAE tax invoice requirements; for the EU and Canada, VAT invoicing for freelancers. If you are not sure, ask your tax authority or an accountant.
What are common invoice mistakes?
- No due date: "Net 30" alone makes the client count. Write the date.
- Vague lines: "Services, $3,000" invites questions and delays.
- Wrong recipient: sending it to your contact instead of accounts payable.
- Missing PO number when the client gave you one.
- No payment details: the client has to ask how to pay.
- Reused invoice numbers: they cause double payments and confusion.
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Frequently Asked Questions
How do I write a simple invoice?
Put "Invoice" at the top, then your details, the client's details, an invoice number, the invoice and due dates, one line per item with quantity and price, the total, and how to pay.
What are the 5 things an invoice must have?
At least: your details and the client's, a unique invoice number, the date, a description of the work with prices, and the total due. Add payment terms and payment details so you get paid on time.
Can I write an invoice myself?
Yes. Anyone can write an invoice. A free invoice generator does the totals and the PDF for you.
Do I need a business to send an invoice?
No. Freelancers and sole traders send invoices under their own name. Check whether you need to register for tax where you live.
How do I write an invoice for hourly work?
Put the hours as the quantity and your hourly rate as the unit price, with the dates or task in the description.
What is the difference between an invoice and a receipt?
An invoice asks for payment. A receipt confirms that payment was made.
