Specify contact website
Supported on: At least Windows Server 2016, Windows 10 Version 1709
Registry
HKLM
SOFTWARE\Policies\Microsoft\Windows Defender Security Center\Enterprise Customization Options
Url text Description
Specify the URL that will be displayed in Windows Security and associated notifications. Users can click on the contact information to visit the specified website. The default web browser will be used. Enabled: Enter the URL in the Options section. Disabled: A contact website URL will not be shown in either Windows Security or any notifications it creates. Not configured: Same as Disabled.