Do you want to open the app which you created with the share extension, when user clicks the share button to use this share extension? If so, this app should be called Containing App.
But unfortunately, there's no way to do this on iOS8.3+ except Today Extension
. From this post we know that:
The intended approach for share extensions is that they handle all of
the necessary work themselves.
Also from the Apple documentation about extension:
An extension’s UI should be simple, restrained, and focused on
facilitating a single task.
Apple doesn't recommend us to open its containing app from extensions, actually it avoids that. If you want to retrieve data in containing app, you can set up an app group so that data can be shared between these two apps.