Follow the instructions in Microsoft's knowledge base to install the policy templates.
The policies are visible in Group Policy editors only if the Microsoft Edge policy templates are installed. Go to Microsoft's Edge landing page to download the Edge policy templates.
User Configuration/Administrative Templates/Windows Components/Microsoft Edge/Configure the Enterprise Mode Site List:.
Computer Configuration/Administrative Templates/Windows Components/Microsoft Edge/Configure the Enterprise Mode Site List:.
User Configuration/Administrative Templates/Windows Components/Microsoft Edge/Configure Internet Explorer integration: IEMode.
Computer Configuration/Administrative Templates/Windows Components/Microsoft Edge/Configure Internet Explorer integration: IEMode.
User Configuration/Administrative Templates/Windows Components/Microsoft Edge/Allow Internet Explorer mode testing: Enabled.
Computer Configuration/Administrative Templates/Windows Components/Microsoft Edge/Allow Internet Explorer mode testing: Enabled.
Enable "Open sites in Internet Explorer mode" on the More Tools menu:.
This setting may not be visible if Edge is controlled by a domain policy.
On the Settings\Default Browser page, click the button to enable Internet Explorer integration mode.
Also accessible by entering the following URL in the address bar: edge://settings/defaultBrowser.
How to enable IE Mode in Chromium-based Microsoft Edge:.