I think that it is after the salutation or before the closing of the letter. If it were a letter, it would look like this:
Dear Dr. Doctor,
(Dear is the Salutation). Body of letter. Body of letter. Body of letter. Body of letter. Body of letter. Body of letter. Body of letter. Body of letter. Body of letter. Body of letter.
Sincerely,
Brainly
Well from what I have seen memoirs are shorter than an autobiography.
Irony would be the correct answer