I once created an iCloud account, which I do not use. Is it possible to delete it? The reason why I would like to do it is so that I can add its email to my current iCloud account, which I am now unable to. Note that I am not talking about the account on the iPhone
You can’t delete them as such, but you can “empty” them. See http://www.wikihow.com/Delete-an-Apple-ID for details.