Start key + PrtScn | SysRq key on the keyboard.
Press and hold the Start key on the keyboard. Then, press the PrtScn key. That’s the key with SysRq under it. The screen should flash (ghost). Release both keys. You can then Ctrl+V (paste) into your target application (document).
Devices by connection
You can still use Alt+PrtScn to snag the selected window or just plain hit PrtScn to get the entire screen copied to the clipboard.
You can get to the On-Screen Keyboard simply by going to the Start screen and typing On-S and it should populate, then hit the Enter key.
Start screen search results
You can right-click that and pin it to the Start menu or Task Bar if you’d like a shortcut either in Desktop or Modern [metro] mode.