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How to make an invoice: a step-by-step guide

24 July 2026 · 6 min read

Making an invoice goes like this: you enter the customer details, add the invoice lines, mark the VAT, set the due date and reference, check the totals, send the invoice as a PDF and track the payment. Below is each step in order. You can get your first invoice out in a few minutes, with no setup.

How to make an invoice step by step

• 1. Customer details: enter the customer's name and address, and the business ID for a business customer. You can save the customer once and pick them from a list next time.
• 2. Invoice lines: add a line for each thing you sold, with a description, quantity and unit price. The line total is calculated for you.
• 3. VAT: choose the tax rate if you are liable for VAT. The program calculates the tax from the rate you enter and itemises it on the invoice.
• 4. Due date and reference: set the payment term, for example two weeks, and give the invoice a reference number so the payment can be matched. The invoice number runs by itself.
• 5. Review: check that the amount without tax, the VAT and the total add up and that the required details are in place.
• 6. Send as a PDF: send the finished invoice to the customer as a PDF.
• 7. Track the payment: mark the invoice as paid when the money arrives, and see at a glance which invoices are still open.

1. Customer details

An invoice starts with who it goes to. Enter the customer's official name and address, and the business ID for a business customer. In Haimoo Invoice you save the customer once in a light customer register, and next time you pick them from a list without retyping.

2. Invoice lines

Add a line for each piece of work or product you sold: a clear description, the quantity and the unit price. The line total and the invoice total are calculated automatically, so you don't need a calculator.

3. Value added tax

If you are liable for VAT, choose the tax rate for the line. The program calculates the tax from the rate you enter and shows the price without tax, the tax and the amount with tax separately. If you are not liable for VAT, you invoice without tax, but it is good to state the reason on the invoice.

4. Due date and reference

Set the due date, for example fourteen days from the invoice date, and give a reference number that lets you match the payment. The running invoice number is created by itself, so the numbering stays in order and no number repeats.

5. Review before sending

Go through the invoice once more: do the amount without tax, the VAT and the total add up, and are the seller and buyer details correct? Because the required fields are ready, the review is quick and nothing essential is left out.

6. Send as a PDF

When the invoice is ready, you send it to the customer as a PDF. On the Starter tier the invoice carries a small Haimoo mark, which disappears when you upgrade to paid. Then the invoice looks entirely like yours.

7. Track the payment

The work doesn't end at sending. Mark the invoice as paid when the money arrives, so you always see which invoices are open and which are handled. That way a reminder goes out in time and no receivable is forgotten.

That is how you make your first invoice as an entrepreneur, from start to finish. In Haimoo Invoice you start for free, make three invoices a month with no card, and upgrade to paid when invoicing grows and you need unlimited invoicing and reports.