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.
If your intent is to persuade the recipient in some way, whether it's to invest money, give you a reference, hire you, partner with you, or fix an issue, create a compelling case for your cause. If, for example, you want the reader to sponsor a charity event, identify any overlap with their company’s philanthropic goals. Convince the reader that helping you would be mutually beneficial, and you will increase your chances of winning their support. Keep your closing paragraph to two sentences. Simply reiterate your reason for writing and thank the reader for considering your request.