If you can’t keep waiting for this feature to be fully availed on the Windows Store, you can still take advantage of this beta release and see how the feature works before your friends get it. Unlike with the case of Android devices where the users can simply download and install an APK file on their devices, those using Windows Phone and would love to test WhatsApp voice calling feature will have to go through the app’s beta testing program.
The beta version that is currently with the WhatsApp voice calling feature is v2.12.40. When making a WhatsApp voice call, users will see a user interface which is very similar to that of the default Windows phone when making a voice call. Just like any other current platform that is enabled with WhatsApp voice calls, Windows Phone devices need to be connected to a high bandwidth of the internet if they want to enjoy the best call quality.