Modify Published Form Template. In this case I select the Personal Forms. Add two text boxes and a button.

On the Settings menu click Settings and then click Form Library Settings. And user can only create form from new content type after that. Then click the Manage Forms button in the Options dialog box.
Under Operative markers you will see them.
Publication Request Form Receive publication requests directly in your inbox. And user can only create form from new content type after that. The check icon indicates that your markers from your template are matching your Google Form. A updates the form template for example adds more fields.