You probably know that WiFi is useful in sending and receiving data because it doesn’t count against your data plan with your carrier, but you probably didn’t realize that you could also use your WiFi for voice calls. This is called WiFi Calling and solves the problem where you don’t have a strong carrier signal, but do have strong WiFi.
Most smartphones support WiFi Calling as do the major carriers. WiFi calling isn’t automatically enabled on smartphones. To turn yours on, go to the Settings menu. On iPhones go to Settings > Cellular and then toggle on WiFi calling. On Android, you’ll generally find WiFi settings under Settings > Networks > Call, where you can then toggle on WiFi calling. Once you activate WiFi calling, you dial as usual. The routing of your call or text is handled automatically in the background and you may see “WiFi” are something similar in the status bar. And, just as with data sent over WiFi, calls made with WiFi Calling do not count against your cellular plan.
By using the builtin WiFi Calling capabilities of your phone, your voice calls are encrypted between your phone and the carrier, so even if you are using a public WiFi hotspot, your voice calls are still protected from WiFi hackers. You can be extra sure by bringing up a VPN connection prior to initiating your voice calls.
WiFi Calling is also useful when traveling internationally in countries where your carrier isn’t available, but WiFi is. This can also be useful in avoiding international charges from your carrier, however, it would be wise to first understand how your carrier charges for WiFi calling in international locations.
You might not want WiFi Calling to be used whenever you are connected to a strong WiFi network, so you may want to toggle WiFi Calling or wireless on and off in locations where you don’t want WiFi Calling to be used (although I would argue that is unnecessary since the calls are encrypted.)