To add websites to Trusted Zones via Group Policy, follow the below in Group Policy Editor.

Computer Configuration > Administrative Tools > Windows Components > Internet Explorer > Internet Control Panel > Security Page and then double click to the “Site to zone assignment list“.

Enable it, click Show, add website as value name and 1, 2, 3 or 4 as value.

  1. Intranet zone
  2. Trusted Sites zone
  3. Internet zone
  4. Restricted Sites zone