If you use iReal Pro on more than one Apple device, iCloud Sync keeps your songs and playlists the same on all of them, automatically. A change on one device, an added song, a new playlist, a transposition, appears on the others the next time you open the app.

 

Even on one device, it keeps a safe copy in iCloud. It is an Apple feature, not on Android or Windows.

 

For more, see Sync your library with iCloud on the iReal Pro website.