When building for an Android device, you need to set permissions for your app to use parts of the system such as the camera, GPS or connecting to the internet. This panel allows you to do this.
The most commonly used permissions are Camera, Internet, Location and barcode scanner support. You can see a complete list of all possible Android permissions and what they allow, here. If your app takes photos and you do not add the Camera permission here, then this will not work in your app and/or your app may crash or freeze when the functionality is accessed.