Where do I find screenshots taken in Minecraft on Windows 10? [duplicate]

If your using the game center feature of Windows 10, you take screenshots by pressing the Win + Alt + PrtScn. (Windows Key + Alt + Print Screen)

You will find the screenshots in your Videos folder, in a sub-folder named Captures. This is the same place game recordings will be placed, as well.

User > Videos > Captures
       or:
C:\Users\[Your username]\Videos\Captures

This answer assumes the Java version of the game is used, not the new Windows 10 version (I have not tried that yet).

If you just created a screenshot, the name of the created file will be shown in the chat stream. Simply click that name to open the screenshot in your default image viewer.

Otherwise, start the MineCraft launcher and activate the 'Edit Profile' button for your current profile. On the newly opened Profile Editor window, activate the 'Open Game Dir' button to open the game directory. A subdirectory of that called 'screenshots' contains your screenshots.