As far as I know, the key is integrated in the BIOS. See also the following article at Medion: https://www.medion.com/ch...
Then there is the following article if the activation does not work: https://www.medion.com/ch...
If you need the licence key for a new installation (or otherwise just like to write it down), you have to read it out of the active operating system: https://www.pcwelt.de/ratgeber...