Answers. 1  Unlike an universal key code to undo, redo doesnt come with a universal Key. This is purely software dependent. SOme use the same key ctrl+Z to redo and undo, some use Ctrl+Y, some ctrl+shift+Z etc... some have multiple levels or undos and so on.. My recommendation is to check the options in the edit menu of that software for more information. Redo In Word. Ctrl + Y is the Redo function for most Windows programs.