You may view DAO No. 19-01, S.2019 (Guidelines in the issuance of a certificate of preference for Domestic Bidders participating in Government Procurement Projects) here.
You may view DAO No. 19-10, S.2019 Amending certain sections of Department Administrative Order No. 19-01 series of 2019 prescribing the guidelines in the issuance of a certificate of preference for domestic bidders participating in government procurement projects here.
You may download application forms through this link.