The proposal argument is one of the most difficult essays to write. It combines what you learned from writing the informational essay and the argument essay. Backup your claims for a need for a change with facts found in reputable sources. Use what you learned about writing an effective argument to make your point stick.
Effective proposal writing is something that will be useful for convincing your boss that something should and can be improved in your work environment. This is known as an "internal proposal" or an attempt to persuade those in charge to get something done (new project or solving an existing problem) within an organization.
Other types of proposal arguments are the "grant proposal" which is aimed to gain support for a nonprofit organization and the "business proposal" which seeks funding from investors or bankers for a new business or an expansion of an existing business.