OnSong can import content from a variety of apps on your iOS device because it integrates with iOS file management. When you receive an email that contains
files that OnSong supports, you can tap to view those files in the built-in Mail app. To import those files into OnSong, you either need to tap on the graphic of the page which is visible if the attachment is a single page PDF file, or on the icon at the bottom of the email message. You will then either be shown a preview of the document, or have an Activities menu appear. If you see a preview screen, tap on the icon in the upper right corner to open the Activities menu.
Once the activities menu is displayed, locate the OnSong icon in the row of color icons and tap to copy the file into your OnSong library. You will then need to confirm importing the file into your library.