How to Write an Invoice (Step-by-Step, with a Free Template)
An invoice is the document that tells a client exactly what they owe, why, and when it is due. Get it wrong and payment slips; get it right and you look professional and get paid faster.
This guide walks through every field a proper invoice needs, the payment terms that actually move money, and a few small touches that shorten the gap between sending an invoice and seeing the cash land.
What every invoice must include
A complete invoice removes any excuse for a slow payment. Whether you hand-build it or use a generator, make sure each of these appears:
- Your business name, address and contact details (and logo if you have one).
- The client's name and billing address.
- A unique invoice number and the invoice date.
- A clear line for each item or service: description, quantity, unit price and line total.
- The subtotal, any tax, discounts, and the grand total due.
- Payment terms and a due date (e.g. "Net 15").
- How to pay — bank transfer details, a card link, or accepted methods.
Number your invoices so nothing gets lost
A sequential invoice number (INV-0001, INV-0002 …) makes your books auditable and gives you and your client a shared reference when chasing a payment. Never reuse a number, and never skip the number entirely — accountants and tax authorities expect it.
If you bill several clients, a prefix per client (ACME-0001) keeps things tidy without breaking the sequence.
Set payment terms that actually get you paid
Terms are the single biggest lever on how fast you get paid. "Due on receipt" or "Net 7" beats "Net 30" for small jobs. State the due date as an explicit calendar date, not just "Net 15", so there is no ambiguity.
Spell out late fees up front if you charge them, and make paying frictionless — a one-click pay link converts far better than "please transfer to the account below".
Send it, then follow up
Send the invoice the moment the work is done — memory and goodwill both fade. If it is not paid by the due date, a short, friendly reminder on day 1 past due recovers most late invoices without any awkwardness.
Keep a copy of every invoice you send. A generator that saves your invoices means you always have the record when a client asks "can you resend #14?".
Frequently asked questions
Do I need to be a registered business to send an invoice?
No. Freelancers and sole proprietors can invoice under their own name. Include your legal name, contact details and (where required) a tax ID.
What is the difference between an invoice and a receipt?
An invoice is a request for payment sent before you are paid; a receipt is proof of payment issued after. Many businesses send both.
How do I number my first invoice?
Start anywhere clean — INV-0001 is common. The only rules are that numbers stay unique and sequential so your records are auditable.
Can I write an invoice for free?
Yes. PaperKit's invoice maker is free to fill in and preview; a small Pro unlock removes the watermark and gives you a clean saved PDF.