In the past, a carbon copy was the under-copy of a document created when carbon paper was placed between the original and the under-copy during the typing or writing of a document. Today, the abbreviations cc (carbon copy) or bcc (blind carbon copy) used in email refer to sending copies of an electronic message to recipients in addition to the addressee.
Nowadays ‘carbon copy’ is often used metaphorically to refer simply to an exact copy. It’s also applied disparagingly to a person who has no personality and tries to emulate yours exactly.
You can use one, two, or three methods of addressing email. The “To” field recipients are the primary audience of the message. The “CC” field recipients are others to whom the author wishes to send the message publicly, and the “BCC” field recipients are addresses which you don’t wish the other recipients to see.
It is still common for a business letter to include, at the end, a list of names preceded by the abbreviation “CC,” indicating that the named persons are to receive copies of the letter, even though carbon paper is no longer used to make the copies.
The term ‘carbon copy’ was used by Robert Heinlein in Stranger in a Strange Land:
“…and you want to turn him into a carbon copy of every fourth-rate conformist in this frightened land!”
If you want to use the phrase as a verb, the abbreviations are: CCed, cc’d, cc’ed, cc-ed and cc:’d. I guess you can pick whichever you like best. Or dislike least.
The first example of the use of ‘carbon copy’ appears to be in the Burlington Hawk-Eye, May 1878, reprinted from the Chicago Post:
“My own plan was to use the Wedgewood carbon copy-book, jotting down scrap notes whenever opportunity offered.”
For ‘carbon copy’ rather than a ‘carbon copy-book,’ the first reference is a piece in The Newark Daily Advocate in March 1888:
“Granville brought out a carbon copy of Mr. Booth’s Times article.”
It’s also, to my surprise, the title of a 1981 movie. Not the most exciting imagery in the world!