Cc refers to the recipient who signs the receipt of the official letter, and has the function of replying to the official letter and inquiring the contents of the official letter from the original letter or other organs and units. The cc person's position on the official letter is at the bottom of the text, and a blank line is written, followed by a full-width colon and the name of the cc institution. Cc refers to other organs, units or personnel who need to know the contents of the official letter, except the sender, the recipient, the personnel who have official contact with the organ or the personnel who have an interest in the contents of this official letter. The cc person's position on the official letter is at the bottom of the text, and a blank line is written, followed by a full-width colon and the name of the cc institution.