Business letter format is the standard method used to craft official correspondence by businesses. There are three business letter formats with the most common being the block style. In the block style, the entire letter is left-justified and single-spaced with a double space between paragraphs.
The modified block and the semi-block are the other business letter formats. The modified block is also widely used. While this style is also left-justified, the date and closing are indented to the center of the page. Least used is the semi-block format. It is formatted like the modified block except that paragraphs are indented, too.