How can I change the default webcam?

If you want to record a video message for your form / a video testimonial, you need to press the 'Record Video' button and permit Trust to use your camera & microphone.

Here you can select the device you need:

Once selected, you can change it later by pressing the 'Settings' button:

If you have issues with mic and camera permissions, please check this article 'No access to camera or micro granted'.