[Your letterhead, if desired; if not, your return address]
[Date of letter-month, day, and year]
[Recipient's first and last names]
[Street or P.O. box address]
[City, State ZIP code]
Dear [recipient's name]:
I am writing to you regarding ______________________ [reason for writing-mention the business-related issue you are writing the letter about, along with all relevant details, etc.]. This ___________________ [assignment, etc.] on __________________________ [dates, details, etc.].
Please ___________________ [action item-RSVP by a certain date, including contact information, etc.]. Thank you for your attention to this matter, and please do not hesitate to contact me if you have questions or need further information.
[Sender's first and last names]