This document provides guidance on writing formal and informal letters. It discusses the key components and format of letters, including the address, date, salutation, introduction, body, and conclusion. For formal letters, the address of the recipient should be included under the sender's address in a specific format. Informal letters use "Dear" followed by the recipient's first name in the salutation. Letters must be carefully written using appropriate language, format, and structure to effectively communicate information to the intended audience.