How do you cc at the end of a business letter?

How do you cc at the end of a business letter?
Before invention of the photocopier, carbon paper was used to create duplicates of documents by placing it between the original document and a blank piece of paper so that an image of the original was transfered to the blank piece of paper as a document was written or typed. A notation was placed at the bottom of the original document indicating for whom a "carbon copy" was created. This notation was typed, for example, as follows:
cc: John Smith
Even with the advent of photocopiers, this traditional notation has carried on, but in recent years some have begun to refer to this notation as a "courtesy copy" notation or even recommend the use of a single "c" to indicate a "copy" is being created to send to someone else. Some reference guides even explain that "cc" also means "copies," in the same way that "pp" means "pages." Regardless of the method used to generate a dupicate of a document, "cc" is still the most commonly used method to indicate copies are being made.