1 Find "Wi-Fi Calling"
Press Settings.
Press Apps.
Press Phone.
Press Wi-Fi Calling.
2 Turn Wi-Fi calling on or off
Press the indicator next to "Wi-Fi Calling on This iPhone" to turn the function on or off.
If you turn on the function, press Enable.
3 Return to the home screen
Slide your finger upwards starting from the bottom of the screen to return to the home screen.