This document provides guidance on writing formal letters, business transaction letters, and letters to the editor. It discusses the major parts of formal letters including sender's address, date, addressee's address, salutation, purpose, closing remarks, and signature. Guidelines are given for writing letters to the editor, such as keeping the letter under 150 words, dealing with one issue, being factual, and including contact information. The format of business transaction letters is also outlined, including sender's address, date, receiver's address, salutation, heading, main body, and conclusion. Types of business letters like inquiry, order, and complaint letters are described.