How do I silence incoming voice calls on WhatsApp?

Solution 1:

In order to silence the ringer during an incoming WhatsApp call, you can turn off all the "Notifications," and prevent the WhatsApp from accessing your microphone by going to Settings > WhatsApp >Notifications. Please note that this will disable all the notifications on WhatsApp including the chat/message notification.

If you'd like to receive sound notification for text/chat and only disable the ringer for incoming WhatsApp call, then you should disable the "Banner" alerts, and prevent the WhatsApp from accessing your microphone by going to Settings > WhatsApp > Notifications.