iOS 11 has released a new Control Center function that allows you to record what's you are doing on your screen. 

1.  Select the Settings > Control Centre > Customise Controls, ​tap on the Green "+" button to add it to Control Center. Now Screen Recording should be under the INCLUDE.
   
        
    
2. Double Tap the Home Button to access Control Center on your iPad. 
    
3. Tap on the Recording icon to record your device screen.
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4. To Record the screen with sound, Touch and Hold on the Recording button and tap on the Microphone icon 
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5. Once you have recorded the screen, tap on the Status bar at the top of the screen and tap on Stop button. 
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6. Your video is now saved in Photos app