How to disable heads up notifications and immersive mode? I recommended purchasing android smart phone (moto e 2015 with android 5.0.2) to a non-technical savy friend of mine and he did. Few UI aspects of android always annoy newcomers. 

One such is incoming call arriving as heads-up notification. I want to disable heads-up notifications for incoming calls or maybe system-wide. Is there any way to do so. The device is not rooted and runs stock android 5.0.2. I already tried this HeadsOff app and it doesn't allow me to select Phone app in free mode. 

Also the device has on-screen navigation buttons alone, like in nexus devices. Whenever any app, say a game takes immersive mode the navbar is hidden and the user feels crazy. Is there any way to disable immersive mode for any or all apps? The device is not rooted and runs stock android 5.0.2.
For the notification issue, try running settings put global heads_up_enabled 0 from adb shell.

For immersive mode: If the device is rooted you could use the Xposed mode App Settings.  It has a Fullscreen setting where you can force disable fullscreen for apps.