The date line is used to indicate the date the letter was written. However, if your letter is completed over a number of days, use the date it was finished in the date line. When writing to companies within the United States, use the American date format. (The United States-based convention for formatting a date places the month before the day. For example: June 11, 2001. ) Write out the month, day and year two inches from the top of the page. Depending which format you are using for your letter, either left justify the date or center it horizontally.