WiFi Calling or VoWiFI was recently enabled by both Jio and Airtel in India and I tested both Jio & Airtel with VoWIFi on various smartphones and I share my experience. I also made calls to smartphone companies like Realme, Asus, Xiaomi to find out if there handsets will support VoWiFi in the future and what you need to enable WiFi calling if you handset supports that.
Airtel WiFi Calling https://www.airtel.in/wifi-calling
Jio Wifi calling https://www.jio.com/en-in/jio-wifi-calling
