How to Make an Invoice That Gets Paid on Time
What belongs on an invoice, the numbering and due-date habits that speed up payment, and how to generate a PDF invoice for free.
The first invoice I ever sent had no due date on it. Just an amount and my bank details. It got paid eleven weeks later, and when I finally chased it, the client’s accounts person was genuinely puzzled: nothing on the document told her when the money was expected, so it sat in a pile behind everything that did.
That’s the whole game. An invoice is a payment instruction, not a receipt, and the ones that get paid fastest are the ones that leave nothing for the other side to figure out.
The fields that actually matter
Legal requirements vary by country, but the working core is short:
- Your business name, address, and tax ID if you have one
- The client’s legal name, not the name of the person you email
- A unique invoice number
- Issue date and, separately, a due date
- One line per thing you’re charging for, with quantity and unit price
- Tax shown as its own line with the rate visible
- The total due, and how to pay it
Two of those trip people up. The client’s legal name matters because accounts payable systems match invoices to vendor records; “Sarah at Northwind” won’t clear, “Northwind Trading Ltd” will. And the tax line has to show the rate, not just the amount, or a bookkeeper has to reverse-engineer it.
Invoice numbers are not decoration
In the EU, Article 226 of the VAT Directive requires a sequential number that uniquely identifies each invoice. Most other tax regimes want something similar. Gaps and duplicates are the sort of thing that turns a routine audit into a longer conversation.
I use YYYY-NNN — 2026-001, 2026-002 — and reset in January. It sorts correctly in a folder, it tells you the year at a glance, and it never collides. What you want to avoid is numbering by client (ACME-1, ACME-2), because then you have several parallel sequences and no single ordered list.
Due dates, and the boring reason they work
“Net 30” is the default in most of the English-speaking world, and the EU Late Payment Directive sets 30 days as the fallback term when a contract is silent. It also entitles you to a minimum €40 in recovery costs plus interest at 8 percentage points above the ECB reference rate. Almost nobody claims either, but mentioning the terms on the invoice changes the tone of the follow-up email.
Write the actual date, not the term. “Due 17 September 2026” beats “Net 30” because nobody has to count. If you want faster money, shorten the term rather than nagging harder — 14 days paid late still beats 30 days paid late.
Making the PDF
The Invoice Generator fills in the mechanical parts. Enter your details and the client’s, add line items, and the amounts, subtotal, discount, and tax recalculate as you type. Discount comes off the subtotal first, then tax is charged on what’s left, which is the order most tax authorities expect. Fourteen currencies are available, and the number formatting follows each one’s convention, so EUR renders as 1 234,56 € and USD as $1,234.56.
Then you download an A4 PDF. No signup, no watermark, no monthly subscription, and none of it touches a server — the document is drawn and packed in your browser, so your client list stays yours. If the line items overflow a page, it continues onto the next with the header repeated.
It won’t chase the payment for you. But it will give the person on the other end nothing to be confused about, which in my experience is most of the battle. Make one now and see how long it takes.