Internet Explorer, along with every other desktop browser, used to support bookmarklets. These lightweight, easy-to-develop scripts can run on any page and provide valuable functionality to users.
Edge no longer supports bookmarklets.
Surely this is one of the reason that some users refuse to move to Edge, and still use MSIE 11.
You can use a free 3rd party application called EdgeManage that will allow you to edit the URLs in a favorite so that it supports bookmarklets
Alan H commented
Users should be able to drag a bookmarklet to their favorites bar to install it. They should be able to right-click one and add it as a bookmark. And they should be able to edit their bookmarks.