Icon says Macintosh HD on desktop

Hi, welcome to the Apple Users Community.

Do not move the icon!!

Click on the desktop background to ensure you are in FINDER the click COMMAND+COMMA (⌘,) to bring up the Finder Preferences like this and click the circled check box:

This will make the icon not show up on your desktop.

Best of luck

You cannot get rid of it, however you can hide it.

Finder - Preferences - General tab (and select the boxes you want).

It is likely the drive that Mac OS is installed on.