Follow these steps to change your camera settings in Teams on a mobile device:

1. Open the Teams app and tap the 'Settings' icon.
2. Under the 'Cameras' section, you can select which one you wish to use, both rear-facing and front-facing cameras.
3. Under the 'Video Settings' section, you can choose to mirror your video, show your camera preview, or switch your camera during a call.
4. Save the changes to apply your new camera settings.