If the extension is from the Chrome Web Store, then you can force install it with a custom Configuration Profile.

The payload would be "Custom Settings:
The preference domain would be "com.google.Chrome"

For uBLock Origin, the plist text would be:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">

<plist version="1.0">

<dict>

    <key>ExtensionInstallForcelist</key>

    <array>

        <string>cjpalhdlnbpafiamejdnhcphjbkeiagm;https://clients2.google.com/service/update2/crx</string>

        <string>cjpalhdlnbpafiamejdnhcphjbkeiagm</string>

    </array>

</dict>

</plist>

Replace cjpalhdlnbpafiamejdnhcphjbkeiagm with the ID of the extension you wish to install which is in the URL of the extension.

Thank you @ryan.ball for your prompt response.
We have two scenarios and would try to implement using the above suggested method in our environment.
- Install the .crx (or unpacked version) in local machine and then use the same local path for loading the extension.
- In this second scenario there is an xml file pointing to the chrome extension (developed internally)
Hopefully this works !!!

Thanks for the help @ryan.ball , the instructions you posted worked perfect in the custom Configuration Profile.

Thanks, that worked but only after I quit and relaunched Chrome the second time.

Nice easy way to do it!

Thanks guys! I was in this ballpark and having issues. Maybe my syntax was off or something, but I used yours and it worked great!

Hi I uploaded plist with Grammarly extention but wheni open Chrome extention is not bein installed.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>ExtensionInstallForcelist</key>
<array>
<string>kbfnbcaeplbcioakkpcpgfkobkghlhen;https://clients2.google.com/service/update2/crx</string>
<string>kbfnbcaeplbcioakkpcpgfkobkghlhen</string>
</array>
</dict>
</plist>

got it to work did new plist file uploaded it and after i launched chrome Grammarly ext was enabled and installed

FYI,

You can only use each key once in Chrome.. if you get asked to force install another extension, then you have to add that to your current Grammarly one and then pull the old profile and then install the new profile with the two extensions.

If you try and send a second extension with a second profile only one will work, I forgot if it's the 1st one or the second one as I was so angry about the time it took me to figure it out... : )

Hope this helps

Any idea how to do this on Firefox?

Take a look at this.
https://github.com/mozilla/policy-templates

Thought I would provide my experience with this as well.
Prerequisites:
- XCode installed
- download Chrome bundle for Windows 64-bit (zip file)
- Extension IDs in PLAIN TEXT file for copy / paste (example)

gmbmikajjgmnabiglmofipeabaddhgne;https://clients2.google.com/service/update2/crx

1. Unpack the Windows Bundle zip file (it creates GoogleChromeEnterpriseBundle64 folder)


2. Navigate to "<extractionfolder>/GoogleChromeEnterpriseBundle64/Configuration/"and move or copy / paste in whichever folder you wish to work.


3. Open the extracted com.google.Chrome.plist file with XCode


4. Turn the pulldown for the "Extensions" attribute


5. add line for each extension you want to add with the correct string for each identifier


6. save the file


7. Create and name the configuration profile


8. Select site/category/distribution method/level desired


9. Select Application & Custom Settings > Configure


10. Select "Upload File(PLIST file)


11. set preference domain to "com.google.Chrome"
    Upload the file, set a test scope and apply.