Installaion
To install the Google Forms add-on, open Google Marketplace and click the blue Install button to add the app in your Google Account.
On the next screen that says “Email Notifications needs your permission in order to start installing”, click the Continue button.
You’ll now be presented with a list of Google accounts that you are currently logged into. Choose the account under which you wish to install and authorize the Forms add-on.
The add-on will now request permissions to access your Google account. Click the Allow button to grant the necessary access and launch the add-on.