Can I use iTunes/Apple Music app playlists in rekordbox for iOS?

You can't directly browse iTunes/Apple Music app playlists in rekordbox for iOS, but you can use them via rekordbox for Mac/Windows in the following way:

1. Right-click the playlist displayed in the [iTunes] category in rekordbox for Mac/Windows and click [Import Playlist].
-> The playlist is copied to the [Playlists] category. (Please note that copied playlists are not synced when you change your iTunes/Apple Music app playlists.)
2. Connect rekordbox for Mac/Windows and rekordbox for iOS to the same Wi-Fi network.
3. In rekordbox for iOS, tap [Connect to rekordbox (Mac/Win)].
4. In rekordbox for Mac/Windows, click [SEARCH MOBILE].
-> The playlist copied in step 1 will be synced to rekordbox for iOS.
5. Right-click the track you want to use in rekordbox for Mac/Windows and click [Mobile Library Sync] > [Transfer to the mobile device].
-> The track will be transferred.