Font Size: The traditional font size for a professional letter is 12. The font should be Times New Roman or Arial. However, if you are using letterhead, the letterhead may be in different font size and style. Font Style: There is no need to use different styles within a professional letter. Use a uniform font (book print font such as Times New Roman or Arial) and avoid underlining, italicizing, or bolding. However, if you are using letterhead, the letterhead may be in a different font style.
Closing the Letter. Choose a Closing: One must use a proper closing in a business letter. Use a comma (,) after it. Sign the Letter: Always sign the letter in ink. If sending a printed copy, always affix the scanned signature. Make Note of Enclosure: One must properly enclose a list of attached documents with the letter. One can use the abbreviation of the enclosure, i.e., Encl. or Enc.