I bought Music Maker 2021, which according to the as includes Sound forge, and indeed, Soundforge is installed on my system, but when I come to open it, it asks for email and serial number. The serial number is not included in my order conformation, as are the other addons. Where can I find the serial for Soundforge?
Have you checked all the information in the email you would have received when your purchase of MM Premium was confirmed? I would expect the serial number for the Soundforge installation to be included there.
If it is not, and assuming you have registered MM and so have a Magix account, go there, log in and check under My Products whether the serial number for Sound Forge Audio Studio 12 is listed. It certainly is in my account.