How do I take a screenshot on a 2021 iPad Pro?

See the following from Take a screenshot on your iPad – Apple Support (UK)

How to take a screenshot on an iPad without a Home button

1. Press the top button and either volume button at the same time.*
2. 
3. 
   
4. Quickly release both buttons.
5. After you take a screenshot, a thumbnail appears temporarily in the bottom left-hand corner of your screen. Tap the thumbnail to open it or swipe left to dismiss it. 

and

Where to find screenshots

Open Photos, then go to Albums > Screenshots.

Please see: Take a screenshot on your iPad - Apple Support