There are three ways you can take a screenshot on Surface Pro 6
Method 1: Surface Hardware Button
Press and hold the power button.
While you hold down the power button, press volume up button on the side of the device. The screen will dim and back to bright again to let you know, a screenshot is recorded. All screenshots you took with this method, will be saved in a folder named Screenshots under Pictures library.
Method 2: Surface Type Cover
Press PrtSn key to taking a full-screen screenshot.
Press Alt + PrtSn key to taking a screenshot of the active window.
Paste to your preferred programs like Paint or Word.
Method 3: Windows Snipping tool
Open the Start menu and type “Snipping Tool”, or you can type into Cortana textbox directly.
You can also open this tool by opening the Start menu and locate the Snipping Tool under Windows Accessories folder.