Proposals are a starting point for your audience to understand your ideas by identifying the key issues, methods and sources you plan to use to develop the project. A proposal will help you complete your project because you’ve thought ahead and made a plan. But proposals aren’t set in stone, and you may have to change the plan as the project unfolds. If writing is not your forte, then hire a professional proposal writer. Types of proposals vary based upon several factors.

Internal vs. External

An internal proposal is meant for a party within your organization, such as your boss at a company or government agency. An external proposal is meant for an individual or organization outside your organization. You may omit certain sections from an internal proposal that you would include in an external proposal, such as your qualifications, according to "Power Tools for Technical Communication.”

Solicited vs. Unsolicited

Often,when individuals or organizations must complete a project, they’ll request that interested parties bid on the job, that is, submit a proposal. This type of proposal is called solicited because it was requested. An unsolicited proposal is one the recipient has not requested. The two differ in that the recipient of an unsolicited proposal may need convincing that the project is necessary.

Business and Financial Proposals

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If you have an idea for a new process at work, then you may write a proposal to explain your plan to the boss. Or perhaps you’re an independent contractor and you want a firm to hire you to complete a certain project. You would write a proposal to explain why and how you’d like to do the project and why you are the right person for the job. Or if you need a loan or investor funds to open a business, then you would write a proposal to the bank or investor explaining how you'll operate business and how you'll use the money.

Sales and Marketing Proposals

If you’re trying to market or sell a good or service, then you might have to write a proposal to prospective buyers and retailers. A sales proposal, for example, would explain your product or service to a prospective buyer and attempt to persuade the buyer to make a purchase. Or if you have a product to market, then you may write a proposal to retail buyers to convince them to sell the product in their stores.

Research Grant Proposals

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Scientific and scholarly researchers who need funding submit proposals for grants to universities, businesses and philanthropic organizations. A grant proposal generally consists of an explanation of the proposed research project and its methods and goals, the qualifications of the researchers and a description of how the researchers will use the funds. Organizations that receive grant proposals, such as the Corporation for Public Broadcasting, provide proposal guidelines.

Book and Article Proposals

Authors who are attempting to pitch an idea for a book or article to a publisher will often submit a proposal. Such proposals generally include an introduction to the author, a description of the proposed piece, an outline and sample chapters or sections.