A request for proposal (RFP) is a formal invitation issued by a business or agency requesting interested vendors to submit written proposals meeting a particular set of requirements.
If interested in bidding for the project, vendors respond with a description of the techniques they would employ to meet the requirements, a plan of work, and a detailed budget for the project, along with supporting information. An RFP may form part of the final contract once negotiations between the enterprise and the vendor are completed.