To install the TIFF Viewer Chrome / Edge extension using Group Policy, Administrators must use the ExtensionInstallForceList policy.
Create new GPO object and navigate to the Policies -> Administrative Templates -> Microsoft Edge -> Extensions:

Double-click on the “Control which extensions are installed silently” option:

Select the Enabled option and click on the Show… option:

Add the following entry: hinllambflhajfhffnaeplcaonpbpkgo;https://clients2.google.com/service/update2/crx

NOTE: To install the Tiff Viewer Chrome / Edge extension, active internet connection is required on the client computer.