How to Format a Formal Letter (wikiHow)Formal letters can come in handy when you need to communicate professionally. Maybe you’re emailing your boss about an upcoming vacation, confirming an appointment, asking for references, or resigning. No matter the case, a well-formatted formal letter can help you correspond with your boss or coworkers in an authoritative and organized manner. In the business world, there are 2 main types of formal letters: block style and Administrative Management Style (AMS). Block style is most widely known, while AMS is for quick internal memos; however, both styles are good to have in your tool belt.