A Request for Proposal or RFP is an invitation for vendors to submit a proposal to the county. Find information about contracting with Hennepin County, including processes, forms, and diversity rules for goods and biddable services.Vendor must complete the Affidavit of Non collusion (Appendix I) and include it with its RFP response. 4. Learn how to write a bid-winning request for proposal with the help of a real-life example and RFP template for inspiration.