Applications can be pinned to the taskbar in Windows 10. Unpinning them is straightforward: right-click on the icon and choose Unpin from taskbar.
However, this does not work on applications that have been pinned by your organization on a work computer using domain rules. You can unpin using the above method, but the pinned applications all return back to being pinned on the taskbar after a reboot.
To permanently unpin these applications, open the file %LOCALAPPDATA%\Microsoft\Windows\Shell\LayoutModification.xml. Find the section delimited by <taskbar:TaskbarPinList> and you will find entries for your pinned applications. Remove these entries and save the file. Go ahead and unpin these applications from the taskbar too. These applications should now remain unpinned even after a reboot.