Letter writing is a form of communication used for personal, professional, and official purposes. There are several types of letter writing, including formal letters, informal letters, business letters, and official letters. Formal letters follow a structured format and are used for professional communication, such as job applications, complaint letters, and business correspondence. Informal letters are personal and written to friends or family members in a casual tone. Business letters are used for corporate communication, including proposals and inquiries. Official letters are sent to government authorities or institutions for requests, permissions, or legal matters. Each type serves a unique purpose and follows specific guidelines.