What is Wi-Fi Calling, and How Does it Work? | Digital Trends
https://www.digitaltrends.com/mobile/wi-fi-calling-guide/
Wi-Fi calling allows you to seamlessly use any Wi-Fi connection to make or receive calls when your network signal is weak. The beauty of Wi-Fi calling is that it should work seamlessly.
Verizon Wi-Fi Calling FAQs
https://www.verizon.com/support/wifi-calling-faqs/
Wi-Fi Calling (aka Voice over Wi-Fi or VoWiFi) is a built-in feature on most of our current smartphones. Wi-Fi Calling lets you make and receive voice calls, texts and video calls over a Wi-Fi network...
4) What types of devices can make Wi-Fi calls?
https://www.nextiva.com/blog/what-is-wifi-calling.html
Wi-Fi calling gives you the chance to make phone calls using a wireless internet connection. It doesn't go through a traditional telecommunications provider like AT&T or Verizon.