Press the Share button in a playlist. (on Mac Control+click on the playlist name)
    1. iReal Pro Format: you can share it with your bandmates via email, AirDrop or any cloud service (Dropbox, Box, Files, GDrive)
    2. Post to Forums: it will copy the playlist to your clipboard. Log in to the forum and paste the content of the clipboard into a post in the related Forum.
    3. PDF: you can share a playlist as a PDF booklet with all the songs in it.
    4. Setlist: you can share the list of songs of that current playlist.
To import the playlist:
iOS:
In Dropbox tap on the file, on the top right, tap on Share, Export and select Copy to iReal Pro.   
In Mail tap and hold the file, select Share and then Copy to iReal Pro.
OS X: Drag and drop the playlist file on top of the iReal Pro app icon in the dock on your desktop.
Android: From email, Dropbox or Google Drive, open the file with iReal Pro.

More info here: