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.
A Note About Email Business Letters. It might be tempting to leave out the closing when you're communicating by email, but don't give in to that temptation. Although no_closing emails are perfectly fine for everyday communication with your friends and teammates, they'll seem brusque – or worse, unprofessional – to people you don't know as well. You should also use a business letter closing when you're corresponding with someone professionally about an important issue, whether it's a new project or a job opportunity.