ASUS - ZenTalk

My smartphone Asus zenfone 6z has got a little yellow mark on the top of the display from yesterday onwards. The touch of the phone has no problem. Is this problem comes under warranty??

How to use picture in picture in Zenfone 6

When I slide down the notification bar at once (or the initial position of the notification bar) to make the phone silent..... many times I press the silent button title it doesn't work........then I again slide down the notification bar then only ...