Gravity Forms is a great tool that allows WordPress users to easily and quickly build and publish forms. It comes with more than 30 pre-configured form fields and can be used seamlessly with a plethora of third-party apps. There are certain other add-ons that can be used as well, including Slack, Dropbox, Zapier, etc. Gravity Forms also has quick and responsive email notifications to alert you each time a visitor fills up a form. If the form or survey requires the users to upload and attach an image, it can be done since Gravity Forms even have a media attachment option. The number of entries and submissions can be limited too, thanks to the feature that allows scheduling any specific form for a particular period of time. The ease of use and a rich list of features make Gravity Forms the best online form builder tool for WordPress.