Good Afternoon,

I am trying to find out the formal rules for writing a business letter. Exacly how many lines down on the page, how many spaces in between items. For example, would you start a letter on line 19 and then put your address, and then drop down two lines and put the address of the person the letter is going to then two spaces below that you would enter the date and then two spaces after that you enter Dear... and then two spaces after that you start the letter and then after the last line, its two spaces and theh you enter the regards, and then four spaces later you put your name and sign right underneath and then two spaces after that you put enc.

I am looking for the exact rules of thumb for the structure of a business letter.

Thank you.