If you want to develop an Android MDM app similar to MaaS360, the best place to start is with the Android Enterprise APIs and Device Policy Controller (DPC) framework. Google provides official documentation on Android Management APIs that cover device and app restrictions. Also, checking out open-source DPC samples can help understand how to implement app control features.

For a concise overview of Android device management concepts, there are some useful write-ups available online that explain how device management works on Android.