HD Voice is activated first while in the Verizon wireless coverage area (can't be activated internationally).
Wi-Fi calls always originate in the US, even when you're outside of the US.
Calls to US numbers are not billed (except for 411 or other premium calls).
Calls to international numbers are billed according to your international long distance plan.
From the Home screen, tap the Phone icon .
If not available, swipe up to display all apps then tap Phone.
Tap the Menu icon (upper-right) then tap Settings.
Tap Call settings then tap Wi-Fi calling.
Tap the Wi-Fi Calling switch (upper-right) to turn on or off .
If turning off, tap TURN OFF WI-FI CALLING when prompted.
If activating Wi-Fi Calling for the first time:
Tap Activate Wi-Fi Calling.
Review the Terms & Conditions then tap CONTINUE.
Ensure the Terms & Conditions option is checked .
Enter the emergency location info (E911) address then tap SAVE.
This info is transmitted to the emergency dispatcher for all 911 Wi-Fi calls. If address validation fails, you'll be required to re-enter a valid address.
Upon successful validation of the address, Wi-Fi Calling turns on.