Magicjack is a free application that assigns you, your own number in the United States, and allows you to make calls for free, receive them and send text messages, the numbers that you call do not have to have this application, also allows you to identify callers.
You can use it from anywhere in the world.
Our advice:
Download it and try it, this app is really useful when you have family or friends in New York and you find yourself in another country or vice versa.
You can download it for Android here: https://goo.gl/z6QWzA or IOS here: https://goo.gl/qTvAZt