This document provides information about letters, emails, and memos. It discusses the key parts and formatting of formal and informal letters. Letters have addresses, dates, salutations, bodies, and complimentary closes. Formal letters are more structured while informal letters can vary in format. Memos are less formal than letters and are used for internal communication within organizations. Memos have a standard format including "To", "From", "CC", "Date", "Subject" lines, and the body. The document compares letters, emails, and memos and outlines their differences.