The Due Diligence Statement (DDS) reference number is generated after submission to the EU information system. It must be passed down the supply chain: when your buyer submits a statement, they must reference the upstream reference number and origin data. Therefore, this is not a form you complete once and forget—it is documentation that must accompany each shipment.
Full details and tariff code list: https://patisco.com/en/eu-check/eudr Check your tariff codes against EU regulations: https://patisco.com/en/eu-check