Facebook launches free calling for all iPhone users in the US | The Verge

Voice is (a feature of) an app

"In early January, Facebook began testing free calling over Wi-Fi and cellular data for all Messenger for iPhone users in Canada, and said that a US launch could be coming soon. Apparently, the test went well — a new free calling button has appeared in the app. Facebook has confirmed to The Verge that the feature began rolling out to US users today, and requires no update through the App Store. To make a call to another Messenger for iPhone user, all you need to do is open a conversation with that person, tap the "i" button in the top-right corner, and tap Free Call."

Facebook launches free calling for all iPhone users in the US | The Verge