VoWIFI enabling Guide

Please make sure both your cell phone and your carrier support VoWIFI

Huawei

No way

Xiaomi

Settings > Connetion & sharing > Reset wifi, mobile & bluetooth

reboots

*#*#4636#*#* test

*#*#86583#*#* Volte

*#*#869434#*#* VoWifi`

When in test > phone info1 , you can see those 4 options enabled:

Mobile Radio Power
VoLTE Provisioned
Video Calling Provisioned
Wifi Calling Provisioned

Setting

https://xiaomi.eu/community/threads/activation-of-volte-and-vowifi-in-xiaomi-eu-rom.63469/

OnePlus

setting > Mobile Network > SIM info & settings

Enable VoLTE calls and Wi-Fi Calling