This document discusses business letters, including what they are, why companies still use them, how to write them, and different types. A business letter is a letter between companies or organizations and their customers or clients. They are still used because executives prefer them and they provide privacy. There are different formats including block and indented, and components like headings, greetings, bodies, and closures. The document provides guidance on how to structure a business letter and examples of different types like sales, orders, complaints and acknowledgment letters.