Visitor Created Post

Gravity Forms allows you to select if a post that is created is a draft, pending review, or published. So while it doesn't have a built in interface for "Moderation", you can use the existing features capabilities to accomplish moderation.

Gravity Forms is designed as a form management solution and while it can create posts from form submissions, it isn't a post/page editor. That is outside the scope of what the plugin is designed to do.

The plugin itself does not have the ability for a visitor to edit their post after it is created. However, in combination with a role management plugin and other available plugins it is possible for you to put something like this together. But it would take being creative with how you implement both Gravity Forms and other plugins to pull it off.