Certificates of Origin require producer sworn declaration of origin with supporting documents; issuance timing, reissue, and recordkeeping rules govern compliance. Final producers or exporters must present a commercial invoice and a sworn declaration certifying fulfilment of origin criteria, listing producer identity, goods description and tariff classification, FOB value, originating and non originating materials with tariff headings, CIF values and percentages, and a description of the manufacturing process. Descriptions must correspond across declaration, invoice and certificate. A producer's declaration may remain valid for up to one year if unchanged. Certificates of Origin must be issued within the prescribed timeframe, valid for a defined period, not issued before the commercial invoice date, and may be reissued as a certified true copy on loss; minor discrepancies do not automatically invalidate a certificate. Issuing authorities must keep sequential records and supporting documents for the statutory retention period.