Professional letters include a wide variety of missives - from resumes to invitations - and can be written in various tones and with various themes.
Even though each letter has a different theme, they should all be prepared according to this outline for a professional letter:
* Sender's Address
* Inside Address (this is the recipient's address)
* Enclosures (whether other pages are attached)
* Typist's initials
The most important thing to remember is to remember to write professionally; use accurate grammar, spelling, and punctuation. This is not the type of letter in which you explain why you quit a particular job or where you went on vacation. These letters can be light-hearted, but they should be written in a professional tone.