App for voip

[Zaft]

Is there an app that will use my cellphone number and data to call instead of using my minutes? I need the app to be the default not the built in phone app from apple. Is this possible?

 

[C DM]

Not sure if there is one that will use your number, but Google Voice (via Google Hangouts) can allow you to make calls using data.

 

[aplnub]

At present, this is not possible. iOS 10 may help considerably.

 

[WarmWinterHat]

The Vonage app lets you make a call out via VOIP and shows your regular number to your caller. You can't receive calls via it, though.

All call are free in the US.