Edge should be pinned to the task bar upon delivery of the OS to your machine.but as in many cases it can be easily moved, without realising.
try going into Start menu/screen, find Microsoft Edge icon, right-click, select "Pin to Taskbar," and done.
Edge should be pinned back at the end of the taskbar.
other ways may help, too:
Don't click on the Microsoft edge icon on the start list. Go to the list of programs (all app.) after you click on the start button and search for the Microsoft edge program (or app) and then right click it. You will see "pin to taskbar" there.
How to Start Edge with Google or Any Custom Start Page