This document provides guidance on formatting and using memos, letters, and emails in a business context. It states that memos are used for internal communication within an organization, especially for more formal topics. Letters are typically sent to recipients outside an organization but may also be used internally for very formal topics. Emails can be used both internally and externally for more informal communication. The document then provides examples and guidelines for formatting elements like date, to, from fields as well as capitalization styles. It also discusses email etiquette and the "Only Handle It Once" or O.H.I.O. principle for efficiently managing communications.