My mother toungue is not English so I would like to know if the usage below is correct or not.

I've seen some people using Mr., Mrs., or Ms. in front of his/her own name as an author of the letter he/she writes. For example at the introduction part of the letter, it says "This is Mr. AUTHOR's-LAST-NAME and I am a sales representative of ....."

I think such saying like Mr., Mrs., or Ms. are honorific prefix to show some respect to the person. So, for me, writhing those prefixes in front of his/her own name sounds a bit odd.

But is it ok, or widely accepted?

Thank you!