This document discusses transactional writing and provides examples of formal and informal letters. Transactional writing has a practical purpose of communication as opposed to creative writing. It includes letters, reports, diaries, dialogues and meeting minutes, each with their own format and rules. An informal friendly letter is conversational in tone and can use contractions, while a formal letter follows specific conventions like addressing the recipient on the left margin, underlining the subject heading, and ending with "Yours faithfully". Examples of each letter type are also provided to illustrate their distinguishing features and structure.