There are a number of hidden apps on Android, which are designed by the developers to make sure the hardware and operation of the phone are working just fine. If you want to find them, it is quite easy and all you need to do is navigate through the home screen setting.
Here, you will see an option for the hide app menu where you will find all the hidden apps that are otherwise invisible. On the contrary, if you see no apps on the device, it means there are no hidden apps present.