Most letters have a standard 1-inch margin on all sides and begin with the return address of the letter writer, followed by four line spaces. Sometimes the side margins for short letters are increased to 1.5-inches.
The two standard types of business letters are block and indented. Block letters are written with no indentations and all text is justified with the left margin. Indented letters have the return address, date, closing and signature indented, centered or justified with the right margin. Business letter paragraphs are written single spaced, with double spaces between paragraphs. Double spacing should also follow the date, the mailing address of the addressee and the salutation. Four spaces should follow the closing to allow room for the signature of the writer above the typed name.