How to enable Wifi-Calling on the iPhone 6
This short tutorial will teach you how to enable the wifi calling feature on the iPhone 6 and iPhone 6 plus. This is currently only available for T-Mobile customers but other carriers might add this feature to their phones in the future.
Step 3: You will now toggle the switch on to Allow wifi calls. If you haven’t already, be sure to update your emergency address before you turn it on. If you do not have an emergency address on file wifi calling might not work. It usually takes in between 10 seconds to 2 minutes for the Wifi Calling feature to start working. It will display as T-Mobile Wifi at the top of your iPhone.