I'll try to be brief.
The portion of the MMA, Music Modernization Act, that I'm most familiar with, and even so I'm not an expert in that domain, has to do with ensuring that there is much less fragmentation of the marketplace in the U.S. Up until now under the MMA, there has been no one central collective for the administration of the reproduction rights in the U.S.
What was happening was that you had lots of different rights holders. There was a difficult infrastructure for the online music services to try to get a central point for licences and/or to get the data flow to be administered, and the payments as well.
The MMA is an attempt—these are my own words—to consolidate this so that it's much more efficient and reaches a larger scope of rights holders out there who may have been missing in the past.