Memos should be used for detailed or sensitive information that is not suitable for email. A memo should state its purpose upfront, either stating what information it provides or what it does. It then fulfills this purpose in the body, which can be broken into subsections if long, and concludes by summarizing key points and indicating who to contact with questions. Memos also have a conventional visual format with headings, blocks of text, and white space for readability, as well as a label indicating it is a memo.