You can receive Messenger video calls on your mobile device, or through a computer running Firefox, Google Chrome or Opera.
You’ll see the names of any contacts who have the app.
You can alternately invite other contacts to download and install Duo.
With Google Duo installed for both you and the person on the other end, you can make and receive both audio and video calls for free.
The only downside: the app is relatively new, so you may not find a lot of your contacts using it yet.
Just fire up the program, find the person you want to call, and tap on the video call button.