To make video call using WhatsApp desktop, just follow these steps below to make a video call using WhatsApp desktop.
1) Open the WhatsApp desktop app on your computer
2) Scan the QR code using your phone (open WhatsApp on your phone > Tap Settings > WhatsApp Web/Desktop)
3) Open the individual chat with the person you want to make a video call to
4) Tap on the Video call icon
5) Tap End Call when you're finished