Difference between letter and memo

Letter	Memo
A letter is short or long message that is sent by one person to another.	Memo is short message that is sent by on e person to another.
Letter is more formal & contains more information.	Memo is informal & it is very short.
A letter is exchange between business & theirs Clint.	Memo is exchange between individual with an organization.
Less attention of grammar in letter.	Less attention of grammar in memo.
Letter is less concise and to the point as compared to a memo.	Memo is more concise and to the point as compared to a letter.