A family of Microsoft word processing software products for creating web, email, and print documents.
If you don't see Ctrl+Z listed under "Current keys" after you have selected EditUndo in the Customize Keyboard dialog box, you can reassign the command.
To reassign the command, leave EditUndo selected as the screen shot shows. Click in the "Press new shortcut key" box, hold Ctrl as you press Z, click the Assign button and then click Close.
If/when you are prompted to save the Normal template, choose to do so.