How do I operate my Mac without a keyboard and/or mouse?

If your mouse or keyboard isn’t working, you might struggle to use macOS to find out why. Activating accessibility settings could help, but that’s also hard without an input device. The obvious answer is to borrow one: any type of USB peripheral should work, and if you can’t get both, you can manage with one of the two. Most macOS features can be accessed with a mouse. If you only have a keyboard, use Cmd-Space Bar (Spotlight) to find and open apps and system features by name. Enter “keyboard” for System Preferences’ Keyboard pane, where in Shortcuts > Keyboard you’ll find reminders of F-key shortcuts. You may need to hold the fn key as well as the function key and modifiers shown (F6 is Ctrl ). Make sure Full Keyboard Access is set to All Controls (press Ctrl-F7). You should now be able to move to wherever you need and Tab to the required option, then hit Space to click or check it.