Mojave's new “Use Stacks” command lets you organize the items on your desktop with a single menu selection (choose View-->Use Stacks) or keyboard shortcut (press Command + Control + 0).
They say a picture is worth a thousand words… here's how it works:
It's that simple.
If your Desktop is a mess, burn that keyboard shortcut — Command + Control + 0 — into your muscle memory and start using it to turn your Desktop clutter into neatly organized stacks.
One last thing: If you're concerned about Stacks messing up your desktop icons, which you've so carefully arranged, you'll be happy to know that pressing Command + Control + 0 again will return your Desktop to its former arrangement no matter how disorganized or messy.