WiFi Calling is a voice-over IP (VoIP) technology. It does not require a cellular signal from all providers, it is an additional service on top of your normal voice and data plans, and there are no roaming charges.
Xiaomi added this feature to most of its smartphones. Does Xiaomi Mi 11 Lite have WiFi Calling? Check it out from here.
WiFi Calling By Xiaomi Mi 11 Lite
Yes, it does support the Wifi Calling feature. This feature has many benefits; when Wi-Fi calling is enabled, you can make and take calls via a Wi-Fi network even if there is little to no network coverage where you are.