How to properly reference the “email version” of a paper business letter at the bottom of that business letter

I need to reference the “email version” of the actual mailed/paper version letter at the bottom of the mailed/paper version. Does that make since?
How to properly reference the “email version” of a paper business letter at the bottom of that business letter
You put





CC: ______@_________.com (with their info filled in, of course)








that's it. the CC stands for Carbon Copy, it just means "a copy of this was sent to...."