Every custom form on the website, built using the Gravity Forms plugin, is mapped to a corresponding form in Act-On. With this mapping in place, every form that is submitted on the website will appear in Act-On as a form submission. Act-On can then push this information into your Salesforce account (when applicable), adding a new lead or updating existing leads or contacts.
This mapping to Act-On is controlled in WordPress under Forms > Act-On Integration. Each Gravity Form has its own mapping to Act-On called a ‘feed’. In the first column, the Act-On fields are listed; in the second, the site fields.