If you’ve navigated away from the Phone app, tap the green bar at the top of your screen, which indicates a live phone call, to get back to the Phone screen.
If you’re using the earbuds that came with your iPhone, press and release the center of the controller on the right earbud wire. If you’ve navigated away from FaceTime, tap the green bar at the top of your screen, which indicates a live call, to get back to the FaceTime screen.
