[Zubersoft]

Looks like an oversight with the file filter. In the open file dialog, just tap the file type dropdown at the bottom right and switch it to "All Files (*.*)" and then you should be able to pick your .wav file. I'll fix this for the next update.

On a side note for anyone that reads this thread, I did just find an issue with the iOS version of MobileSheets where you can't add audio files through the companion app, but that will require an update to the iOS version.

Mike