Billingz Guides · Invoicing

How to make an invoice that gets paid

Short answer

An invoice needs seven things: your details, the client’s details, a unique sequential number, the date, a clear description of the work, the amount with any tax broken out, and a due date with payment instructions. Everything else is decoration.

Most unpaid invoices are not disputes. They are invoices that were unclear, late, or easy to ignore. The mechanics below fix all three.

What an invoice must contain

Your business details - legal name, address, and tax or registration number where required.
The client's details - the exact legal entity paying you, not just a first name.
A unique invoice number - sequential, no gaps.
Issue date - and the supply date if it differs.
A clear description - what was delivered, in words the client's accountant understands.
Amounts - net, any VAT or tax as its own line, and the total.
Due date and payment details - exact date, bank account or payment link, and the currency.

Numbering that will not embarrass you

Pick one format and never break the sequence: something like 2026-001, 2026-002 is enough. Gaps and duplicates are the first thing a tax inspection notices, and renumbering after the fact is painful. A system that assigns numbers automatically removes the problem entirely.

The same rule is why an issued invoice is never edited. When one goes out wrong, the correction is a separate document: how to correct an invoice with a credit note. And if you need to ask for money before the work exists, that is a third document again, set out in pro forma, invoice, credit note.

When to send it

The day the work is delivered - not at the end of the month. Every day between delivery and invoice is a day added to your real payment time, and it signals that payment is not urgent to you either. Deliver, invoice, same day.

It is worth knowing what happens next on the other side, because everything your client types into their bank is read off your invoice: how a payment order is filled in.

The details that get invoices paid faster

A date, not a formula. "Due 26 July 2026" beats "net 14".
One total, impossible to misread. If there are several currencies or items, the payable number still has to be singular and obvious.
The client's PO or reference - if their accounting needs a reference, missing it can add weeks.
A fixed reminder rhythm - day 1, day 7, day 14 after the due date. Polite, short, consistent.

What to say at each of those points, and what EU law already entitles you to once an invoice is late, is set out in what you are owed when an invoice is not paid.

Bank transfer, payment link, direct debit

Most invoicing tools now offer a card payment link alongside the bank details, and the question of which to put on the invoice is usually asked as if it were a choice. It is not. The bank details belong there regardless, and the link is a second door.

What is worth understanding is what the second door costs, because the cost is yours and not the client’s.

The client pays the same either way. - the invoice total does not change. What changes is how much of it reaches you.
Card processing takes a percentage. - commonly around 1.5% plus a small fixed fee for cards issued inside the EEA, and two to three times that for cards issued outside it. On a EUR 1,000 invoice paid by a European card, roughly EUR 984 lands.
The money is faster to send and slower to arrive. - the client pays in seconds, then the processor pays out on its own cycle rather than yours.
Payouts arrive batched and net. - several payments, minus fees, in one line on your statement. That line will never match a single invoice, which is the part that surprises people at reconciliation.
A transfer inside SEPA costs nothing to either side. - but it asks the client to type six fields correctly, and a wrong reference is how a paid invoice becomes a chase.

So the link earns its percentage where friction is what delays you: smaller amounts, new clients, anyone abroad for whom a transfer is slow and expensive. It earns less where a reliable client already pays a large invoice on time, because there you are paying a fee to solve a problem you do not have.

There is a third door, and it is the one freelancers ask about least and would sometimes benefit from most. With a SEPA direct debit the client signs a mandate once and you pull the money on the due date, so nothing depends on anybody remembering. It suits retainers and anything recurring, and it does not suit one-off project work.

You need a creditor identifier. - issued by your own bank, and it goes on every mandate. This is the step that stops most sole traders, since not every bank will give one to a very small account.
Each client signs a mandate. - with your creditor identifier and a unique mandate reference. A recurring mandate lapses if unused for 36 months.
The Core scheme can be reversed. - the payer may demand the money back within eight weeks without giving any reason at all. Money collected is not money settled until that window closes.
The B2B scheme cannot. - the debtor's bank verifies the mandate up front and there is no refund right afterwards, which is why it exists. It is only available between businesses.

So direct debit trades effort for certainty at the start: more paperwork before the first payment, and then nothing to chase. For a freelancer with three monthly retainers it is worth the setup. For a freelancer with twelve different clients a year it is not.

Whichever they use, the amount landing in your account can differ from the amount you invoiced, and for the same reason each time: something was taken on the way. The other versions of that are in international payments and exchange rate differences.

Common questions

Is an invoice legally required?

For business-to-business sales in most countries, yes - and B2C rules vary. Even where it is not strictly required, an invoice is your payment record and your proof in any dispute. Send one for every job.

What is the difference between an invoice and a receipt?

An invoice requests payment - it is sent before money moves. A receipt confirms payment - it is issued after. They are not interchangeable documents.

How should I number invoices?

Sequentially and without gaps: a simple prefix plus a counter, like 2026-014. Most tax authorities expect an unbroken sequence, and it keeps your own records honest.

What payment terms should I set?

Common terms are 14 or 30 days. Shorter terms get paid faster. State the exact due date on the invoice rather than only "net 14" - a date removes arithmetic and excuses.

What do I do when an invoice is not paid on time?

Send a short, polite reminder the day after the due date, then follow a fixed rhythm - for example day 1, day 7, day 14. Consistency, not aggression, is what collects. Late-payment interest rules vary by country.

Built for this

Billingz creates cleanly numbered invoices and shows where every invoice stands - sent, due, late, and paid, in one view.

See how Billingz handles invoicing

This guide is general information, not legal or tax advice. Invoice requirements vary by country. Confirm specifics with a qualified accountant. Reviewed August 2026.