Desktop icons on the taskbar are small graphical representations of applications, files, or folders that are pinned to the taskbar for easy access. They allow users to quickly launch their favorite applications, access frequently used files or folders, and perform various tasks.
If you are looking for a clickable icon (like the old Windows XP/7 Quick Launch bar) that actually sits on the taskbar rather than in the corner, you can create a custom toolbar: desktop icon on taskbar