In the spirit of giving you even more flexibility and customization, we’re launching add-ons for Google Forms–new tools, created by developer partners, that bring even more features to your surveys (just like add-ons for Docs and Sheets).
Check out the growing list of available add-ons, several of which are particularly relevant for education, from the “Add-ons” menu in Forms, or by directly visiting the Forms add-ons store.
If you have already disabled add-ons for your domain in the Admin console, Forms add-ons will be defaulted off. To change this setting, click on Google Apps -> Drive > General Settings and check/un-check the “Allow users to install Google Docs add-ons” box.
Rapid release and Scheduled release
Reference by www.google.com