A Request for Proposals (RFP) from the Minnesota Department of Commerce is a formal invitation to potential contractors or grantees to submit a proposal. Pre-letting (how to bid). Steps.Sign the bid form manually in ink. Here are some of the forms you may encounter: Bid bond. – Request for a Certificate of Liability Insurance from the vendor. A Request for Proposal (RFP) is a formal invitation to potential contractors or grantees to submit a proposal. A listing of requests for proposals (RFPs) from League of Minnesota Cities member cities seeking expertise and services from vendors.