The Best Formatting for a Business Letter. A business letter is a formal document often sent from one company to another or from a company to its clients, employees, and stakeholders, for example. Business letters are used for professional correspondence between individuals, as well. Although email has taken over as the most common form of correspondence, printed out business letters are still used for many important, serious types of correspondence, including reference letters, employment verification, job offers, and more.
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.