What to put on an invoice: a field-by-field checklist
An invoice that is missing a field does not bounce — it sits in someone's accounts inbox until they get round to asking you about it. These are the fields, and the reasons each one is there.
Why an incomplete invoice is expensive
A business customer's accounts department matches your invoice against a purchase order, a delivery record and a supplier account. If any of the three cannot be matched, the invoice does not get rejected — it gets *parked*, which is worse, because nobody tells you. The first you hear of it is when the payment does not arrive.
Nearly every parked invoice is missing one of four things: a purchase-order or job reference, the buyer's correct legal name, a tax number, or bank details. All four take seconds to add and none of them can be added after the fact without reissuing the document.
The checklist
Identifying the document
- The word "Invoice" — or "Tax Invoice" where your rules require that exact wording.
- An invoice number, unique and sequential. Gaps and duplicates are what an auditor looks for first.
- The issue date — when you raised it.
- The date of supply — when the work was actually done or the goods delivered. Often a different date, and in tax terms usually the more important one, because the tax period follows the supply rather than the paperwork.
- The due date. See how to write payment terms.
Who is selling
- Your legal name — the entity that contracts, which may not be your trading name.
- Your address, and contact email and phone.
- Your tax registration number, if you are registered.
- Your commercial registration number, where your jurisdiction uses one. It is a different identifier from the tax number and a buyer checks both.
- Your logo — not required, but it is what makes an invoice recognisable in a long accounts inbox.
Who is buying
- Their legal name, spelled as it appears on their registration. "Acme" and "Acme Trading Co. Ltd" are not interchangeable to an accounts system.
- Their address.
- A named contact — the person who ordered the work, so the invoice reaches someone who recognises it.
- Their tax number, which is required on a tax invoice in most VAT systems when the buyer is a registered business.
- Their reference — the purchase order or job number. This is the single most common reason for a parked invoice.
What you are charging for
- A description per line that a person who was not in the room can understand. "Consulting" is not one; "Site survey and report, Building B, 12–14 September" is.
- Quantity, and a unit where it clarifies things — hours, days, pcs, m².
- Unit price.
- Any discount, shown as a line rather than quietly folded into the price.
- The tax rate on each line. Set per line, not once for the document, so a bill mixing rates still totals correctly.
The money
- Subtotal before tax.
- Tax, as its own figure — a total that silently includes tax cannot be reclaimed by the buyer.
- The grand total.
- The currency, named explicitly. "$" is at least four different currencies.
- How to pay — bank name, account number, IBAN, and whatever reference you want quoted back.
A worked example
- Line
- Site survey and report — 1 × SAR 2,000.00
- Discount at 10%
- − SAR 200.00
- Subtotal
- SAR 1,800.00
- Tax at 15%
- SAR 270.00
- Total due
- SAR 2,070.00
Note the order: the discount comes off before the tax is worked out, because tax is charged on what the customer actually pays, not on the list price. Reversing those two steps overstates the tax.
If you need to check that arithmetic from the other direction — a total that already includes tax — see how to calculate VAT.
Extra fields on a Saudi tax invoice
Saudi e-invoicing rules add requirements beyond the general list above. Three of them show up as fields you might not recognise:
- The VAT registration number of the seller, and of the buyer when the buyer is registered.
- The commercial registration (CR) number, which is separate from the VAT number.
- An additional number — an identifier for the business itself, printed in the letterhead. It has nothing to do with the invoice number and takes no part in numbering.
The rules also require a QR code on the invoice carrying five values as an encoded string: the seller's name, their VAT number, a timestamp, the total including VAT, and the VAT amount. The Invoice Generator produces that code automatically — but only when a VAT number has been saved, because a code encoding a registration that does not exist is worse than no code at all. An invoice without a VAT number simply prints without one.
Building it in BuzPulse
Fill in your details once
The seller block — name, address, tax number, CR number, logo, default currency — is saved to your business profile and reused by the invoice and quotation tools, so it is typed once rather than per document.
Add the customer
Type them in, or pick them from the address book so the name, address and tax number come across exactly as they were last recorded.
Add the lines
Description, quantity, unit, unit price, and the discount and tax rate for that line. The totals update as you type.
Set the dates
Issue date, supply date, and a due date — choosing a payment term fills the due date for you.
Add payment instructions
Bank details and any reference you want quoted. This is the field most often left empty and the one that most reliably delays payment.
Check the preview, then download
The preview is the PDF. What you see is what the customer receives.
The mistakes worth checking for
- No purchase-order reference when the customer uses them.
- A trading name instead of the legal entity on either side.
- Tax folded into the unit price with no separate tax figure, leaving the buyer unable to reclaim it.
- A currency symbol with no currency code.
- Discount applied after tax. It belongs before.
- A due date with no stated term, or a term with no matching date. The two should say the same thing.
- Reusing an invoice number after voiding one. Void it and move on; never reissue the number.
Frequently asked questions
- Does an invoice need to be signed?
- Generally no. What makes it valid is the required content, the numbering and the record behind it, not a signature.
- What if I am not registered for tax?
- Then you do not charge it and you do not show a tax line. Leave the tax rate at zero and leave the tax number blank — the invoice prints without a VAT number and without a ZATCA QR code, which is the correct output for an unregistered seller.
- Can I change an invoice after sending it?
- Not quietly. The usual practice is to issue a credit note against it and raise a corrected invoice with a new number, so the trail shows what happened.
- What is the difference between the issue date and the supply date?
- The issue date is when you raised the document; the supply date is when the work was actually delivered. Work finished in August and invoiced in September has two different dates, and the tax period follows the supply.
- Do I need an account to make an invoice?
- No. The public generator builds and downloads a PDF in your browser. An account is what saves the invoice, assigns sequential numbering and keeps a list you can come back to.
The tools behind this
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About the author
Naeem Ahmed builds and runs BuzPulse. These guides describe tools he has built, and they describe how those tools actually behave — including where they stop.
Corrections and questions: nsglobal6@gmail.com
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