A proposal is an offer to carry out research or provide a product or service in order to persuade readers to accept it. There are two types of proposals: internal proposals within an organization, and external proposals which can be solicited or unsolicited. A proposal delivers information about a problem or meets a client's need. It is a persuasive document that must demonstrate an understanding of the reader's needs, convince the reader of the writer's ability to fulfill promises, and emphasize benefits for the reader such as cost savings and improved services. A successful proposal sells an idea through an informative yet persuasive document that keeps the audience in mind throughout.