If you use iReal Pro on more than one iCloud device, such as a Mac, an iPad, and an iPhone, iCloud Sync keeps your songs and playlists the same on all of them. When you make a change on one device, adding a song, creating a playlist, transposing a chart, and so on, it is saved to iCloud automatically. The next time you open iReal Pro on another device, it downloads the change and updates your library.
Even if you use iReal Pro on only one device, iCloud Sync keeps a safe copy of your songs and playlists in iCloud, in case the device is lost or broken or you upgrade to a new one.
iCloud Sync uses very little space, about 5 to 30 MB of the 5 GB that Apple includes free with every iCloud account.
To turn it on, see Set up iCloud Sync.