Carbon copy -- abbreviated cc:, CC: or c.c. -- is a notation added to the bottom of letters indicating that it has been sent simultaneously to more than one recipient. Carbon copy is used typically for business, formal and legal correspondence. The notation is placed at the end of the letter below the signature, initials and enclosure, if the latter two are present. Since carbon paper is seldom used today, "cc" is referred to also as "courtesy copy."
Type your letter normally, finishing with the signature line.
Drop down two lines on your page and, flush with the left-hand margin, type CC:, cc: or c.c.
Indicate the name of the other person to whom the letter is being sent. If there is more than one other recipient, separate each name with a comma.