Invoice anatomy guide

What should an invoice include?

An ordinary business invoice commonly identifies the seller and customer, an invoice number and date, what was supplied, quantities or rates, prices, applicable tax, the total due, a payment deadline and payment instructions. Exact legal requirements vary by country, seller status and transaction, so check the relevant local rules where required.

Reviewed: 27 September 2026

Field by field

What each part of an invoice is for

These are the fields that commonly appear on a business invoice and what each one is for. Not every invoice needs every field — some only apply when tax, references or specific payment methods are relevant.

Common invoice fields
FieldWhat it's for
Seller identityThe business or person issuing the invoice — name, and the contact or registration details they choose or are required to provide.
CustomerWho is being billed. Review the name and address against your own customer record.
Invoice numberA unique reference used to identify this invoice in your records and in messages with the customer.
Issue dateThe date the invoice was created or sent.
Goods/services descriptionA clear description of what was supplied — the work done, items delivered, or service provided.
Quantity/hoursHow much of the item or service is being billed — units, hours, or a count.
Unit/rateThe price per unit, hour, or item before totals are calculated.
SubtotalThe sum of the line items before tax or adjustments are applied.
Tax/VAT where applicableThe tax rate and amount that apply to this invoice, if any. See VAT and reverse charge for how tax treatment can vary.
TotalThe final amount requested, after tax and any adjustments.
Due date/payment termsWhen payment is expected and any agreed terms, such as Net 30. See payment terms for common options.
Payment instructionsThe account, reference, or method the customer should use to pay.
Reference/PO where applicableA purchase order or internal reference number the customer's own records may require.

To see these fields applied to a finished fictional invoice, view the annotated invoice example.

Where country-specific rules take over

The fields above describe what an invoice commonly includes, not a universal legal checklist. Exact requirements — additional identifiers, mandatory wording, numbering rules, or e-invoicing formats — depend on the seller's country, business status, and the transaction itself. Check the requirements for the relevant jurisdiction before relying on this guide alone:

A dedicated Finnish invoice-requirements guide does not exist yet; see the Finnish tools and resources in the meantime.

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Turn this into your own invoice

Describe the client, work and price in plain language and InvoiceCraftly prepares a reviewable, editable invoice draft using these same fields.

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Before you send

Confirm what applies to you

This guide explains common invoice fields and their purpose; it does not state every legal requirement for every country, seller type, or transaction. Confirm the exact requirements, tax treatment, and payment terms that apply to your invoice, customer, and jurisdiction before sending it. Use the invoice readiness checklist to review an invoice before it goes out.