In practice: it should show the seller and buyer, invoice number and date, a full description of each item with its HS code, quantity, unit and total price, currency, Incoterm and country of origin, and be signed or stamped where the destination requires it. Declared values that do not match payments or reference values lead to reassessment and penalties. Some destinations add checks: Iraq requires electronic verification of invoices since 10 July 2026, and the UAE has required attestation of invoices above a set value since 2023.

Example: the invoice total, the bank transfer and the declared value all show the same amount, so the valuation step in Iraq passes without a query.