Use Professional Formatting
Use company letterhead and formal block style, the standard business letter format, if you are sending a payment request letter by mail or fax. Depending on your company's correspondence procedures, it may also be acceptable for you to transmit the letter via email. If so, it's better to include the letter in the body of the email message rather than as an attachment file. It is not necessary to create a letterhead template for an email message, but you should close the communication with your official company email signature line.