In practice: customs uses origin to apply the right duty, preferential rates under trade agreements, quotas or restrictions. Non-preferential certificates simply state origin; preferential ones let the buyer claim a reduced rate under a specific agreement. The origin must match the invoice and the product markings. In China, certificates are issued by bodies such as CCPIT and China Customs. Since 10 July 2026, Iraq has required certificates of origin to be verified electronically before a declaration is processed.

Example: a supplier in Yiwu obtains a certificate of origin for a mixed shipment; the Iraqi importer's broker verifies it electronically, and only then is the ASYCUDA declaration accepted.