A Proposal Letter is a document submitted in response to a request for proposal (also called an RFP) from a potential customer or client. It outlines the proposed solution to their problem and briefly explains why your company is the best option for providing that solution. Proposal Letters are persuasive documents, designed to convince the reader of the merits of working with your company. They should be engaging, yet concise, outlining the key features of your product or service in an accessible way. Ultimately, a Proposal Letter needs to demonstrate why your company is the right choice for the opportunity.