This document provides guidance on writing formal and informal letters and emails. It discusses including a greeting, introduction, main body organized into paragraphs by topic, and appropriate closing. For informal letters, each paragraph should have a topic sentence and use present perfect or simple past tense appropriately. When giving advice, both formal and informal letters should include opening remarks to introduce the request for advice, suggestions for courses of action using formal or informal language, and closing remarks thanking the recipient. The document also provides examples of language for writing letters of complaint.