As we work, sometimes we end up with many open windows. I am guilty of this and sometimes end up with as many as twenty or more open windows, cluttering up my screen.
You can however, minimize every open application window and Finder window by using a keyboard shortcut: Command Option H M (⌘ ⌥ H M)
This will hide everything except for the Desktop. Your open windows and application are still there, but they are minimized on the Dock – click the associated dock icon to redisplay an application or Finder window.