Which document type is generally not considered official correspondence?

The designation of a personal letter as generally not considered official correspondence is accurate due to its nature and purpose. Personal letters are typically informal and are written between individuals for personal reasons, such as sharing personal news or friendship matters, rather than for official or formal communication within an organization or the military.

In contrast, a memo is a type of internal communication used to document and convey information within an organization succinctly. Business letters are formal documents that often follow a strict structure and are used for professional and official matters, such as inquiries, contract negotiations, or formal requests. A joint letter, which is typically signed by multiple individuals, can also be an official correspondence if it concerns matters relevant to an organization or collaborative effort.

Thus, while memos, business letters, and joint letters serve formal communication purposes, personal letters do not meet these criteria, making the distinction clear.