ReCaptcha on form

Hi all! I’m wondering if anyone knows how to apply a Captcha (ReCaptcha) to a form that is not located in the root (index.html) of a website. I tried white labeling the addresses on the Google ReCaptcha platform but it says that it only allows to register Captchas on the root folder.

I’m on a deadline, so any help would be greatly appreciated.

Best,
Angel