To share or backup your songs, tap the button in the upper right corner of the screen. Then choose the option Export Songbook. All your songs are added to a zip file named iPadSongs.zip. It can take a few seconds, depending on the size of your songbook. When it finishes, you can send the file via email. If you prefer, you can connect the iPad to a computer, start iTunes in the computer, then copy the file using iTunes File Sharing (click on the Applications tab, then, under the section File Sharing, click on the icon for this app).

To import the songs into the iPad, you have to extract the .zip file in a computer, and then copy the resulting .txt files to the app using iTunes File Sharing – see https://support.apple.com/en-us/HT201301.