When do you send a memorandum instead of a letter?

A memorandum is typically used for internal communication within an organization, often to convey information, updates, or decisions to employees or departments. It is more formal than an email but less formal than a letter, making it suitable for quick, concise communications. You would choose a memorandum over a letter when the message is intended for multiple recipients within the same organization or when addressing specific policies or procedures. Letters, on the other hand, are more appropriate for external communications or formal correspondence with clients and stakeholders.