This article explains how to take a screenshot on any Surface device.
How to take a screenshot on MICROSOFT Surface
Most Surface devices take a screenshot when certain buttons are pressed simultaneously. The shortcut varies by device.
If successful, your Surface device should dim or flash its screen briefly. You may see a notification saying that a screenshot was saved to this folder:
The Surface Duo, which runs Android, saves screenshots in a different location. If you use Google Photos, look in Library > Screenshots. If you use OneDrive, the folder is Photos > Explore > Screenshots.