How can I switch from an audio call to a video call and vice versa?

On desktop:

During an audio call:

• Click    Video Call to switch on the camera.
• Click    Video Call again to turn off the camera.

During a video call:

• Click    Video Call to turn off the camera and switch to an audio call from your side. Your contact's camera will remain on.

For instructions on how to do this on mobile, click here.