I’ve showed this trick in one of my videos, but I think it is worth showing with screenshots. Here’s a guide how to export track from GarageBand to other apps.
1st step: Export Track from GarageBand to email
Open MySongs page in GarageBand, push the Edit button (on the top right corner of the screen) and select the song you want to export.
Choose Mail option and you’ll see Share Song window, click Email in the top right corner and you’ll see the picture below:
Push there Cancel button and choose Save Draft. So mail draft with you file attached would be saved in the mailbox.
2. Open Song from email in another app (Audioshare for example)
So now you need to open Mail App, go to the iCloud/Drafts folder and open saved draft.
You’ll see same email with song attached but you can’t open the attachment while email is in the draft folder.
Now press the Trash icon. And your mail will be moved to Trash folder.
Go to the iCloud/Trash folder and open same email. You’ll see that now attachment is active. So tap and hold on the file and you’ll see standard Open in… dialog.
Now you the export track from GarageBand trick is done and your GarageBand song can be opened in any app that support m4a files.
Some apps support only wav files or AudioBus or AudioCopy so I recommend to use AudioShare to convert between file formats and sharing formats.