How to Write a Professional Invoice
A clear invoice is the difference between being paid next week and chasing a client for a month. It is also a legal and tax document in most countries, so the details matter. This guide explains what to include, how to structure it and how to get paid faster.
What an invoice is for
An invoice is a request for payment that records what you delivered, what it costs and when it is due. Your client uses it for their accounting, and you use it for your own records and taxes. Missing or unclear details are one of the most common reasons payments are delayed.
What every invoice should include
Your details
Your name or business name, address, email and, where required, a tax or VAT number. Requirements differ by country, so check what is mandatory where you live.
Client details
The client's name or company, address and a contact person. If the client is a company, make sure the name matches their legal entity, because their accounting team will reject mismatches.
Invoice number and dates
Give each invoice a unique number in a consistent format, such as 2026-001, 2026-002. Add the issue date and the due date. Sequential numbers also help you and the tax authority see that nothing is missing.
Line items
Describe each service clearly, with the quantity or hours, the rate and the line total. Instead of just writing design work, write homepage design, 10 hours at 50 per hour. A clear description prevents questions.
Totals and tax
Show the subtotal, any tax or VAT and the final total. For example, 10 hours at 50 is 500, and with 20% tax of 100 the total due is 600. If you do not charge tax, say why if your country requires it.
Payment terms and methods
State the due date and how to pay: bank details, a payment link or another method. Common terms are net 14 or net 30, meaning due 14 or 30 days after the invoice date. Add the late fee if you charge one.
Tips to get paid faster
Send the invoice as soon as the work is delivered, not at the end of the month.
Make the due date obvious and use shorter terms, such as 14 days, if clients accept them.
Offer an easy payment method, such as a payment link.
Send it to the right person, usually whoever handles accounts payable.
Send a friendly reminder a day or two after the due date.
Deposits and milestone invoices
For larger projects, invoice in stages: a deposit before you start, a payment at a milestone and a final payment on delivery. This reduces your risk and keeps cash flowing.
Common mistakes
Missing invoice numbers or duplicate numbers.
Vague descriptions such as services.
No due date, which gives the client no deadline.
Sending the invoice to the wrong person.
Forgetting to keep a copy for your records and taxes.
Keep your records
Store every invoice you send, along with proof of payment. Tax authorities often require you to keep these records for several years, and the exact period depends on your country.
Create one now
Our free invoice generator lets you fill in the details and save the result as a PDF in your browser, with nothing stored on our servers. For overdue invoices, see our guide on handling late-paying clients, and use the template pack for reminder emails and an editable invoice file.