Sync Library from Cloud
With an Apple Music or iTunes Match subscription, Sync Library makes your music library available through Apple cloud services.
Turn On Sync Library
Section titled “Turn On Sync Library”On your iPhone or iPad, navigate to Settings → Apps → Music. Turn on Sync Library.
Depending on the size of your music library, syncing may take some time. You can use the Apple Music app to view your library and track progress.
Once the library has been synced, your music will appear in Hi-Fi.