Peek at Desktop allows you to click on the furthest right-hand corner of the Taskbar to preview your Desktop without having to minimize any windows. You can also disable this feature if you like.
Turn Peek at Desktop on or Off in Windows 10 - Peek Button
Right-click on Peek at the far-right corner.
Check or uncheck Peek at Desktop.
Turn Peek at Desktop on or Off in Windows 10 - Settings