Kids want to play a game on your Android phone but you’re scared of what they might open or do then Pin the app so they can only access that app. This is available in android phones with Lollipop (5.0) and above. Settings have to be on for this Settings – Security – Pin Windows. Chose to turn on screen pinning and whether to set a lock to unpin (wise to do).
To use it, open the app you want to pin, tap the Overview button on the bottom of your phone screen (the square button that usually shows recently opened apps). Drag the title bar for the app you are using to pin up until it is in the middle of the screen. In the bottom right corner of the app there will be a blue pin button. Tap on it. Confirm your choice when asked.
To unpin, press and hold Overview and Back keys at the same time. And then unlock if you set that option.
Note it will block notifications and other functions like calling and messaging.