How to Install Form Builder for Docs
Create a new Google Doc or open any of your Google Doc.
Now click on "Add-on" option from the menu .
Then click on "Get Add-on" option from the menu
search for "Form Builder for Docs"
Select Form Builder for Docs from the search result and click on Domain Install or Individual Install
It will take you to the Authentication window and select your account
Click Allow that will complete your Authentication process.
That's It. your installation process is Completed.
Click on "DOMAIN/INDIVIDUAL INSTALL" button
Follow the steps above.