WiFi calling is perfect for those of us that just cant get very good mobile phone coverage and most phones now support WiFi calling.
Wi-Fi Calling lets you make and receive voice and video calls over a Wi-Fi connection instead of using your cellular connection. If you have a Wi-Fi connection and are in an area where voice service is weak or unavailable, use Wi-Fi calling to continue making voice calls.
If you have weak cellular signal where you are but have an internet connection via the NBN (excluding satellite broadband) or Mobile Broadband you can make use of WiFi calling wherever you have a WiFi Signal.
By broadcasting or extending your WiFi signal outside or to poor cellular coverage areas of you residence or property you gain the ability to not just access the internet but to make and receive phone calls.
Wi-Fi calling is generally included at no additional charge on compatible devices.
Your device must be HD Voice capable to use Wi-Fi Calling.
Most new phones do support WiFi calling.
On android devices is simply a matter of checking your settings and ensuring WiFi calling is enabled .
On Apple devices see the following link.