Formal letter format Formal letter format by Expert Writer - October 5, 2014February 7, 20200 A formal letter is a type of letter articulating formal note, and it is used most for the business purposes, in correspondence, when submitting requests, making complaints, etc. Formal letters are written mostly in a cases when your correspondent is someone you do not know in person, however, except in business, when it is used to preserve business practice. Writing formal letters requires that sender must follow certain rules for writing formal letters.. However, formal letter must articulate clear and precise message, and therefore it should be short and concise as possible, up to one page, with no more than 3 paragraphs, unless the subject requires more space. Nevertheless, formal letter must be written in envisaged design, which distinguishes these letters from informal ones. In business practice there are four types of formal letters, and they are as follows: Full Block Letter Format Semi-block Format Modified Block Format Modified Semi-block Format Please follow the links above to see particular design of the specified types of formal letters.