How to Use Really Hidden Fields
Render in HTML allows you to make a Hidden field invisible in the HTML markup. With this feature, any Hidden field in the form becomes more secure, which is paramount when using Payment Gateways (PayPal/Stripe).
Render in HTML is turned on by default. This way, the Hidden field type will be seen in the page’s source code.
If you disable the Render in HTML toggle, the Hidden field will disappear in the HTML markup and be secured.
The Render in HTML feature works with all Field value types of the Hidden Field although there are two exceptions. The Hidden Field won’t be secure if it is set to URL Query Variable or when using a preset with URL Query Variable set as a source.
If Referer URL is chosen, the Render in HTML toggle won’t be available meaning that this feature is turned on by default.