Insurance: kindly arrange your own travel and medical insurance (if required for visa purposes).
Letter for visa application: Please write to firstname.lastname@example.org, email reference: Letter request for visa. Kindly provide me with the following details in your mail:
Full name (as stated in passport):
Home/Organization address, postcode, city, country:
Date of birth:
Passport validity: DD/MM/YYYY
To whom should the letter be addressed to: Embassy/Consulate of XXX, and/or a particular department and mention a specific item that should be visible on the letter if needed. A general letter could also just be issued under your name.