FTP servers do not support the Copy command, and to do so with code in excel will be more challenging and require a lot of efforts since you will have to bypass several FTP protocals.
Additionally, FTP protocol does not allow you to retain the original file and create a copy on other folder.
To copy a file or folder from one remote folder to another:
Download the file.
Upload the file to a new location. Another option is to perform a site-to-site transfer, if your server allows that.
Note:
Some servers do not allow site-to-site transfers
You can copy a file by downloading the file and then uploading again to a new destination folder, or by performing a site-to-site transfer on the same site if the server allows it.
Copy command is in the main menu because, you can copy files from the remote to the local pane, or to the queue, and so on.