Written communication is a form of communication that is composed of written words, symbols, and numbers. It is used to convey messages, ideas, and information between two or more people. Two common forms of written communication are memos and letters. A MEMO is a short written message, usually sent within an organization, that conveys information quickly and efficiently. A LETTER is a longer written message, often sent between two people who are not in the same organization, that conveys more detailed information.