The eleven elements
Everything below appears on a well-formed invoice. A few are legally required in most countries; the rest are there because leaving them off costs you time or money.
| Element | What it does | If you leave it off |
|---|---|---|
| The word “Invoice” | Identifies the document type | It gets filed as correspondence rather than routed for payment |
| Your business details | Says who is owed and how to reach them | Queries go unanswered and payments arrive unmatched |
| Your tax registration number | Makes it a valid tax invoice | A registered customer may be unable to reclaim the tax and may reject it |
| Customer’s legal name and address | Identifies who owes the money | Their system cannot match it to a supplier record |
| Purchase order number | Links the invoice to the authorisation | With larger customers it is usually rejected automatically |
| Invoice number | A unique reference for both sides | Neither party can identify which invoice is in question |
| Invoice date | Sets the accounting period and starts the clock | Payment terms have no start point |
| Due date | Says when payment is expected | “Soon” is not enforceable, and you cannot chase from a fixed point |
| Itemised lines | Shows what is being paid for | The invoice is queried before it is approved |
| Tax and discounts | Shows how the total was reached | The figures do not reconcile and the customer asks |
| Total and payment details | The amount and how to pay it | The customer emails to ask, and the invoice waits |
Need the invoice now? The free invoice creator does the arithmetic and downloads a PDF. No signup.
What varies by country
Tax authorities set their own requirements, and they differ more than people expect. Common additions include:
- The customer’s tax number on business-to-business supplies, particularly cross-border.
- A tax point or supply date distinct from the invoice date.
- Wording such as “Tax Invoice” on the face of the document.
- Product classification codes — HSN or SAC codes on Indian GST invoices, for example.
- Statements about who accounts for the tax under reverse-charge rules.
- Sequential numbering without gaps, which some authorities require explicitly.
Check your own tax authority’s current guidance before you rely on a format. See the tax invoice guide for how these fields are entered.
What does not belong on an invoice
- A price you have not agreed. An invoice is not the place to introduce a number for the first time.
- Vague line descriptions. “Services rendered” guarantees a query.
- Terms the customer has never seen. A late-payment charge that first appears on the invoice is generally unenforceable.
- Internal codes with no explanation. Your job reference means nothing to them unless you label it.
- A due date you do not intend to enforce. Terms you never follow up train customers to ignore them.
The fields most often forgotten
Payment details
Bank details or a payment link. Astonishingly common to omit, and it stops the invoice dead.
The purchase order number
Ask for it before you invoice, not after it is rejected.
The delivery or service address
When it differs from the billing address, the customer may not be able to allocate the cost.
The currency
A bare “$” is ambiguous across at least a dozen countries. Name the currency.
Deposits already paid
Show them as a deduction on the invoice rather than relying on the customer to remember.
Invoice & Quotation Generator for AndroidThe same fields, saved and reused on every document.
Install free
Questions
Is an invoice a legal document?
It is a commercial document that records a debt and is normally admissible as evidence of it. It is not a contract by itself — the contract is what you agreed beforehand. What an invoice must contain to be valid for tax purposes is set by your own tax authority.
Does an invoice need a signature?
Usually not. Some jurisdictions and some customers require one on particular document types, and certain export documents do. Check the specific requirement rather than assuming either way.
What is the difference between an invoice and a statement?
An invoice bills one transaction. A statement lists all outstanding invoices for a customer at a point in time. A statement is a reminder; it is not itself a demand for a specific new debt.
Should the invoice show the delivery address?
Yes when it differs from the billing address. Customers with several sites often cannot approve an invoice without knowing which one it relates to.
Keep reading
Make the document: invoice creator · receipt maker · quotation maker · waybill maker · Word templates