The short answer
Put seven things on a page: who you are, who owes you money, a unique invoice number, the date and the due date, an itemised list of what you supplied with quantities and prices, any tax, and the total. Save it as a PDF and send it to whoever pays. Everything below is detail on getting each of those right.
Need the invoice now? The free invoice creator does the arithmetic and downloads a PDF. No signup.
Step 1 — Head the document “Invoice”
It sounds trivial. It is not. An accounts department handles quotations, delivery notes, statements, credit notes and invoices, and routes them differently. A document that does not say what it is gets filed rather than paid.
Step 2 — Your business details
Trading name, address, email and phone number. Add your tax registration number if you have one; in most countries an invoice from a registered business is not valid without it, and your customer may not be able to reclaim the tax.
Use the name your customer will see on their bank statement. If you trade as “Riverbend Design” but the account is in your personal name, say so on the invoice — unmatched payments create work for both of you.
Step 3 — Customer details
The legal entity that owes the money, not the person you talk to. For a company, use the registered name. Add their tax number where they are registered and it is required, and their purchase order number if they use them — with larger organisations, a missing PO number is the single most common reason an invoice is rejected without explanation.
Step 4 — Invoice number
Unique, and ideally sequential. INV-001, INV-002, and so on. Never reuse a
number, even for a corrected invoice — issue a credit note and a fresh invoice instead. See
how to create an invoice number.
Step 5 — Dates
Two of them, and they do different jobs.
- Invoice date — the date of issue. It determines the accounting period and starts the payment clock.
- Due date — the date you expect to be paid. Write it as an actual date. “30 days” is ambiguous; “24 April 2026” is not.
Step 6 — The line items
This is the part that decides whether your invoice is approved or queried. Each line needs a description specific enough to be recognised weeks later by someone who was not involved.
| Weak | Strong |
|---|---|
| Design work | Homepage and product page redesign — per proposal PRO-018 |
| Labour | Labour, second fix — 4–8 March, 2 operatives, 4 days |
| Consulting | Advisory retainer — March 2026, per SOW-2026-04 |
| Parts | Consumer unit, 10-way metal clad, and 4× RCBO 32A |
| Extra work | Variation VO-03 — additional socket runs, instructed 6 March |
Each line carries a quantity and a unit price, and the line amount is quantity × rate. Keep the unit consistent with how you priced the work: hours for hourly work, days for day rates, units for goods, and 1 for a fixed fee.
Step 7 — Tax, discounts and extras
Tax goes on its own line with the rate visible, never rolled into unit prices. A discount goes on its own line so the original price and the concession are both on record. Delivery, travel or other charges get their own line too. See how to add tax and how to add a discount.
Step 8 — The total, and how to pay it
One total, clearly the largest figure on the page, in a named currency. Then the practical part people forget: how to pay. Bank details, a payment link, or whatever you accept, in the notes. An invoice that does not say how to pay it gets an email asking, and then waits.
Step 9 — Notes and terms
Notes are for the customer — a thank you, payment details, a delivery reference. Terms are the conditions: when payment is due, what happens if it is late, and anything specific to the job. Both belong on the document rather than in the email, because the document is what gets filed.
Step 10 — Send it as a PDF
Export to PDF and attach it. A PDF looks the same on every device, cannot be edited by accident and is what accounting systems expect. See creating a PDF invoice and how to send it.
A quick checklist before you send
- The word “Invoice” is on it
- The invoice number has not been used before
- The customer’s legal name is correct
- The PO number is included, if they use one
- Every line has a quantity and a rate, and the total is right
- The due date is an actual date
- Tax is a separate line with the rate shown
- Payment details are on the document
- It is a PDF, named so it can be found again
Invoice & Quotation Generator for AndroidCreate invoices, receipts, quotations and waybills on your phone.
Install free
Questions
Can I write an invoice by hand?
Legally, in most places, yes — an invoice is defined by what it contains, not how it was produced. In practice a typed PDF is easier to file, harder to dispute and expected by business customers.
Do I need to be a registered business to send an invoice?
You can invoice as a sole trader or individual in most countries. Whether you must register, and at what point, depends on local rules and your turnover. Check with your own tax authority.
What if I made a mistake on an invoice I already sent?
Do not edit and resend under the same number. Issue a credit note cancelling the original, then a new invoice with the next number. That keeps the numbering sequence intact for both sides.
How soon should I send an invoice?
As soon as the work is complete or the goods are delivered. The payment clock starts on the invoice date, so every day of delay is a day added to the end.
Keep reading
Make the document: invoice creator · receipt maker · quotation maker · waybill maker · Word templates