(2) A procurement unit shall include in an invitation for bids: (a) a description of the procurement item that the procurement unit seeks;. Contract or of any competing bids or proposals.Description: REQUEST FOR PROPOSALS. Estimates, bids, and proposals are used to negotiate a sale, whereas a contract is a legally binding agreement. Please provide proposals that fit within this budget amount. A construction proposal is a document used to provide a client with a clear understanding of a project's details.