Memorandum
He wrote an office memo.
The plural form for the noun memo is memos.
The word "memo" is used in Georgian to refer to grandmother.
Memory
memo is a clipped word
enclosure
be sponsered
Email?
be sponsered
note, memo
The noun 'memo' is a singular, common, concrete noun; a word for a type of business correspondence; a shortened form of the noun memorandum; a word for a thing.
There are many memo formats and templates available. Your computer's word processing software probably has a few pre-loaded. Most memorandums include the name of the person sending the memo, the receiver's name, the date, the subject, and then the body of the memo.