Since the beginning of iOS, the screenshot process consisted of simultaneously pressing the standby key and the home key. The screen flashes, a shutter sound sounds from the camera, and the screenshot is saved to your camera roll.
With the reinvention of iOS devices that do not have a start button, starting with the iPhone X and now with the new iPad Pro. The banal task of taking a screenshot has changed.
To take a screenshot with the new iPad Pro, press the Standby button (button on top of the iPad Pro) and the volume up button at the same time.
This is not the case Keep the buttons pressed for a long time. Just make sure you push them at the same time, and you'll be familiar with the screen flash and the camera shutter sound.