Apple apparently thinks that you’d prefer not to see the icons for your Mac’s built-in hard drive, solid-state drive, or those of any external drives on the desktop of macOS. However, I want those icons on my desktop. If you’re like me, here’s how to make them show up.
Click on the desktop so the Finder is “active.”
Select Preferences under the Finder menu (it’s at the top left hand side of the screen).
You’ll see a list of items on your desktop. Check the ones (hard disks, external disks; CDs, DVS, and iPods; connected services) you want to be visible.
Voila. Icons for those items now appear on your Mac’s screen.
Also, in the past, you could customize your Mac’s drive icons if you wanted. However, that ability seems to have changed with macOS Mojave. If anyone knows how to do this, please post in the comments!