The Universal Extensions are available in the Chrome web store for download and can be pushed out through the console to users under Chrome management or out to Chrome devices "Chromebooks".
Chrome Management:
Push out extensions via Google Apps for Education:
Log into the Google Admin console.
Go to Device Management > Chrome > Apps & extensions>User&browsers
Select your OU.
Click on the Addition Settings Cog
Click on Edit under the Chrome Web Store
Select your Chrome web store app setting.
Click on Save.
Click on the X in the upper right to close the settings.
Select your OU.
Click on the yellow circle with the plus sign in it.
Select add from the Chrome Web Store.
"Recommended Apps and Extensions".
Search for and select the extensions that you want to add to the user's profile.
Wait for the app to appear in the middle column.
Click on the app to set install permissions.
*You can also Force-install the Apps and Extensions so users can not remove or tamper with them. See How to force-install