Create your first invoice for free — step-by-step guide 2026

You've sold something — a service, a product, a gig — and now you need to create an invoice. Maybe for the first time. The good news: it's simpler than it sounds, and you can do it entirely free online. This guide walks you through it step by step, from what the invoice must contain to how you send it and get paid.

What a valid invoice must contain

An invoice isn't just a receipt — it's an accounting record, so the law sets requirements. To be legally valid in the EU it must contain:

• Invoice date
• A unique sequential number — chronological and unbroken
• Your name and address (the seller)
• Your company or VAT number
• The customer's name and address
• A description of the goods or service
• Amount excluding VAT, VAT rate and VAT amount
• Total to pay
• Due date and payment details (IBAN or similar)

Step by step: create the invoice

Step 1 — Fill in the sender (you)

Your business name, address and company/VAT number. Do it once and it's saved for next time.

Step 2 — Add the customer

Name, address and email. Save recurring customers so you don't re-type them.

Step 3 — Add invoice lines

One line per item: description, quantity, unit price and VAT rate. The total is calculated automatically.

Step 4 — Set dates and payment terms

The invoice date is usually today; the due date follows your payment terms (30 days net is common). The number is set automatically in the right series.

Step 5 — Review and save

Check the mandatory fields and the total, then save — the invoice gets its number and becomes an accounting record.

PDF and sending

When done, the tool generates a PDF — the format everyone can open. From there you can send it directly by email or download the PDF to print or send another way. Sending through the tool also gives you a trail: you see when it was sent and can send a reminder if it goes unpaid.

Payment terms — choosing the right one

• 30 days net is standard for B2B customers
• 10–14 days suits consumers and smaller amounts — shorter terms mean faster payment
• Late interest — you may charge interest on late payment; state it on the invoice

Common mistakes to avoid

1. Skipping numbers — numbering must be unbroken; use the system's auto-numbering
2. Forgetting VAT — a wrong or missing rate makes the invoice hard to post
3. Vague description — "miscellaneous" won't do
4. No due date — the customer won't know when to pay
5. Deleting an invoice — issue a credit note instead of deleting the original
6. Paper only — you must keep the invoice for years; digital is safer

Summary

Creating an invoice comes down to three things: the right mandatory details, a correct sequential number and clear payment terms. A good tool handles the rest — calculations, PDF, sending, reminders — and you can start for free.

Try our free invoice generator, read more about creating an invoice online, or see how 1invoice.online works for businesses and freelancers.