I might have deleted system preferences, how can I reinstall

The joy of System Settings moving everything around, and dropping some things that System Preferences used to do. Only iPad and iPhone users switching to the Mac will find System Settings enjoyable. The rest of us, just scream 😱

Start by using the search box in System Settings. That can generally find the section you need to play with.

If you Home Screen, you mean your desktop wallpaper, then search for "wallpaper" and you will find it.

If you mean something else by "Home Screen" please attempt to clarify, as IdrisSeabright has asked.

It's not possible to delete Settings. Click on the Apple Menu (it's an actual apple icon) on the far left of the menu bar. You should see Settings.

Note that if you have an older version of macOS, it's called "Preferences".

Ventura replaced it with System Settings.

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What do you mean by "Home Screen"? What do you mean by "update" it? Home Screens are something that iPads and iPhones have, not Macs. What device are you asking about?