On Main Menu
> Scroll to the bottom
> Tap Other Options
> Tap Advanced
> Scroll to the bottom
> Tap Android Settings
> Tap Continue
> Tap Yes
> Tap Open Network & Internet
> Tap Mobile Network
> Tap the option you see
> Confirm VoLTE is on (if slider is to the right, it is on. It is usually switched on by default)
> Tap Advanced
> Tap slider to the right of "Use Wi-Fi calling" to confirm on
> Tap Calling Preference
> Select whether you would prefer to prioritise Wi-Fi or Cellular Calling as you like