The newer devices that are enabled for 4G or higher also support VoLTE telephony. If VoLTE telephony is not activated on your device, you can do this under “Settings - Mobile Networks - VoLTE Calls” or by searching in Settings.
If it is not clear whether your device is VoLTE-enabled, you can test it. If your device displays 4G but this disappears when you make a call, then VoLTE is not switched on or your device is not VoLTE-enabled.
VoLTE