This document provides guidance on the structure and components of a formal letter. A formal letter includes a heading with the sender's address and date, the recipient's address, a salutation, an introduction stating the purpose, a body with relevant details in 2-4 paragraphs, a conclusion suggesting action or closing remarks, and a signature with the sender's full name. The document also provides templates for writing letters of complaint, including common phrases for the introduction expressing dissatisfaction and the final paragraph hoping for resolution or further action.