What provides an informal means of correspondence within a Navy activity?

The memo serves as an informal means of correspondence within a Navy activity. It is commonly used for quick, straightforward communication that does not require the extensive formalities associated with letters or directives. Memos are designed for internal communication and facilitate the exchange of information between personnel within the same organization. They are often used to convey brief messages, announcements, or updates that are relevant to the activities of the unit.

In contrast, letters are typically more formal and used for communication outside the organization or for situations requiring a more official tone. Directives have a commanding nature and are used to issue orders or policies that require compliance, while reports present findings or information, usually in a structured and detailed format. This contrast highlights the memo's utility in providing a less formal, yet effective method of communication within Navy activities.