I have no idea what "be a partner on youtube" means, but if you're not using any copyrighted material (other than your own, that is), you can do whatever you want.
Yes, according to youtube terms for partnership the work should be yours(you can read their terms). As in this case using Magix Music Maker 16 for making music commercially is ok no need of any kind of commercial license. Even if you use Music Maker 16 soundpool that is also ok just avoid, Soundpool 17, 18 they need commercial license.