WhatsApp video calling lets you place a video call to anyone using WhatsApp. Video calling is only available to users who are on Android OS 4.1+, iOS 8.0+ and Windows Phone 8.1+. If your system OS is not supported, video calling will not be available to you.
To place a WhatsApp video call, simply open the chat with the person you want to video call and tap on the phone button on top. Then tap Video call.
When someone video calls you, you will see an incoming WhatsApp video call screen. You can slide the green button to answer the video call, or slide the red button to decline the video call. Alternatively, you can tap on the message icon on the video call screen to decline the video call with a quick message.