You may be in the process of updating or testing a new form that you are not ready to be found by the public. Alternatively, you may only give access to a form via emailing a link so do not want it to be presented in search results.
Within the form settings you can opt to manage the form visibility.
Select to edit your form, then select form settings from the three more action dots in the top right. Scroll in the settings to Visibility and select the toggle to activate and hide your form from Google and other search results. Publish the form with this updated setting and although live the only way it can be accessed is directly via the form link.