On your iPad Pro, iPad Air 2, or iPad mini 4, you'll find Mute 
and Rotation Lock 
in the Control Center. Swipe up from the bottom of the screen to open the Control Center.
Turn on Mute
From the Control Center, tap . When Mute is on, you won't hear audio for notifications, alerts, or sound effects like keyboard clicking. You'll still hear audio playback in your music, podcasts, videos, and games.
To turn off all system sounds including audio playback, touch and hold the Volume Down button.
Turn on Orientation Lock
From the Control Center, tap . When Orientation Lock is on, your screen will stay in either portrait or landscape mode and won't rotate as you move the device.