To make voice call using WhatsApp desktop, just follow these steps below to make a voice 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 call to
4. Click on the voice call icon
5. Tap on End Call when you're done