With an active Apple Music subscription, it's very easy to add new music to your iTunes library.
When you subscribe to Apple Music, you can add to your own iTunes music library the many millions of tracks available through the service. It's important to note, however, that you don't own these tracks. Really, you're renting them. So if you sign out of Apple Music, or let your subscription expire or lapse, these tracks will disappear.
Full story from the iMore Blog...