. . . . Which version of the music maker auto mastering function come with . . . .
The Plus and Premium versions - you could add it to the free version at additional cost, however in the long run it is more economical to buy one of these versions they save you money compared to adding features etc piecemeal.
Chosse you optional extras carefully after downloading and installing the additional extras that come with the 2 variants - once chosen and installed there is no changing your mind.
See the comparison chart for what you get with the 2 variants compared to the free version.