On this post I'll show you how to pin to screen on android.
If you don't know what pin to screen is, pin to screen is a feature that got added to android from lollipop version, it enables your android screen to display just one app without showing the notification bar, here's how it is, you launch your email app pi it to screen, no matter what happens on your phone your screen doesn't leave the email app, even notifications on the notification bar are not shown.


To Activate Pin to screen on your android, Go to your Settings and scroll to and tap on 'Security', scroll to 'Screen pinning' Tap on it on the next page Tap on the toggle button at the top right corner to activate the Screen pinning on your phone, below it is an other toggle 'Lock Device when Unpinning'(I'll talk about this later).

After activating the screen pinning feature on your android you would want to pin an app to your screen.Open the app you want to pin to screen, tap the Overview button on your android(the square button on your android on some phones its not square shaped).

After that you'd be shown the app switcher on the last app you opened is a pin icon tap on it to pin the app to screen. Done the app is pinned.

Should you want to unpin the app hold the back and overview buttons and it'll be unpinned.

Now, back to the 'Lock Device When Unpinning' enabling this Toggle ensures that after unpinning an app, your screen still remains locked such that you can't use it for anything, this becomes handy when you want to prevent some people from making use of your device with the screen pinning feature

don't hesitate to ask any question

source; http://www.legitstuffs.com/2016/01/how-to-pin-app-to-screen-on-android.html