WS Form includes a Conversion Tracking action that can fire Facebook Tracking Pixel events from your forms in WordPress.
You can choose Facebook (Standard) to select an event name and add optional object properties. You can also choose Facebook (Custom) to manually enter the event name and define object properties as key value pairs.
For Facebook conversion tracking to work, a Facebook Tracking Pixel must already be installed on your website. WS Form also lets you enter straight text or use WS Form variables in these settings.