Gravity Forms Live Preview shows a form as it would appear on the frontend. You pick the options from the Preview button on the form.

Show Hidden makes hidden fields visible, so you can confirm they hold the expected value. Unrequire skips required validation and bypasses reCAPTCHA, so you fill in only the fields under test. Single Page folds a multi-page form into one page. Enable AJAX loads the form with AJAX on or off. Disable Notifications stops notifications from sending, and Ignore Form Restrictions skips limits such as Limit number of entries, Schedule Form and Require user to be logged in.

These preview controls are part of the Gravity Forms Dev Tools add-on. It also adds Query Monitor logging, admin bar form and plugin managers, auto field naming, a dummy entry generator and a dummy payment gateway.