How to restart an iPhone 11 and iPhone 11 Pro
1. Quickly press and release the UP button Volume as picture 1
2. Quickly press and release the Down Volume button as picture 2
3. Press and hold the side button until Apple logo appear and then release the side button as picture 3
Note: The screen will go down for a while don’t panic your phone is restarting. A few second apple logo and menu screen appear again that your phone is restart completely.