Automated Clearing House (ACH) Vendor Authorization Form. All vendors/grantees doing business with the City of Portland are required to enroll in the City’s ACH Vendor Payment Program. Email  competitivespecialappropriations@portlandoregon.gov to receive a copy of the form. Once completed, send the form along with a copy of a voided to competitivespecialappropriations@portlandoregon.gov.