How to use undo option in Windows 8 Paint?
Undo is used to remove the previous action.
Option 1: Use the shortcut key Ctrl+ Z.
Option 2: Click the left arrow given above the home tab.
In the below image, you can view the previous action undone in the image.
If you are not able to find the undo icon, then add that option to Quick access toolbar by the following step,
Select Customize Quick Access Toolbar icon and select Undo.
You can undo all the previous actions by continuously pressing the Undo icon/Ctrl+ Z to bring the original image.