Almost every Windows app supports at least a simple, one-step Undo. To undo an action you just performed in Windows, press Ctrl+Z on your keyboard.

Some applications (such as Adobe Photoshop and Microsoft Office) support multiple steps of Undo, taking you back another step each time you perform the Undo command. If so, you can keep pressing and releasing Ctrl+Z to go back as many steps as you need.

• Also, in many applications—such as Microsoft Office apps—you can press Ctrl+Y or F4 on your keyboard to Redo the action you just undid.

In many apps that have a classic “File / Edit” menu bar at the top of the window, you can perform an Undo by clicking “Edit” and selecting “Undo” in the menu that appears.

Likewise, some apps place a “Redo” option just below “Undo” in the “Edit” menu . But the classic File / Edit menu bar is getting harder to find in Windows. Instead, some apps such as Microsoft Word (and other Office apps) include special Undo and Redo toolbar buttons.

• To perform an Undo in Office apps, click the curved, left-pointing arrow in the Quick Access Toolbar at the very top of the window.

To perform a redo that will bring back what you did undid, click the Redo button in the Quick Access toolbar, which looks like a hooked arrow pointing to the right.

Other apps with different toolbar interfaces will likely have different designs for their undo or redo buttons. In general, look for a curved arrow pointing to the left for “Undo.” You can also try right-clicking in a text entry area and looking for an “Undo” option. Or, when all else fails, try pressing Ctrl+Z on your keyboard.