You can change nearly any desktop icon on both Mac and PC. To change desktop icons on a Mac, open the "Get Info" menu and paste in the picture you want to use. On a PC you'll need to make a .ICO file, ...
If the macOS desktop is looking a little boring, or is in need of a little more personalization than a change of background image, one solution could be to change how files, folders, and apps look.
Your computer's hard drive uses a system of folders to help organize the tens of thousands of files on it. A folder is not a file itself, but contains files such as word-processing documents, videos ...