I've copied my manager as he will need to provide approval. As per Jon Hanna's second example, you can also use this parenthetically: My manager (copied) will need to provide approval. My manager (copied in) will need to provide approval. As per MT_Head's comment you may also see "copy on", although to me it sounds more natural to use "copy in on": More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.