Enable Automatic Downloads on Your Library
On the other hand, if you want to save up as much data as possible, you can always download your favorite songs. You do that by tapping on the cloud icon next to each song or inside of a playlist.
Apple Music can also download automatically every song you add to your Library. This is not as simple as tapping on the cloud icon.
Instead, you should go to Settings and then select the Apple Music option. Scroll down to the ‘Downloads’ section and enable Automatic Downloads.