he memorandum, usually called a memo, is a common form of internal communication in business and academia. Memos have many purposes, including informing employees, giving directions, outlining procedures, requesting data, supplying responses, and confirming decisions. But essentially there are three basic reasons to write a memo:
To persuade to action (we should do this)
To issue a directive (do this)
To provide a report (here’s what was done, or here’s what we found out)