The Facebook pixel receives these types of data:
Http Headers – Anything present in HTTP headers. HTTP Headers are a standard web protocol sent between any browser request and any server on the internet. HTTP Headers include IP addresses, information about the web browser, page location, document, referrer and person using the website.
Pixel-specific Data – Includes Pixel ID and the Facebook Cookie.
Button Click Data – Includes any buttons clicked by site visitors, the labels of those buttons and any pages visited as a result of the button clicks.
Optional Values – Developers and marketers can optionally choose to send additional information about the visit through conversion tracking. Example custom data events are conversion value, page type, and more.
Form Field Names – Includes website field names like ‘email’, ‘address’, ‘quantity’ for when you purchase a product or service.