How to Quickly Switch to Windows Desktop and Switch back to Current Window

Very often we need to switch to Windows desktop to check something from there, then maybe we want to switch back to current window. How can we do it quickly?

Method 1: Most people might know this way – Click the small rectangle on the bottom right corner to switch between desktop and current window:

Method 2: This way is actually faster than Method 1 and it is more convenient. However it looks like fewer people know or use it. This method is recommended by us:

Just use Windows Key + D to switch between desktop and current window.