reCaptcha not working

Hi,
I see Really Simple Captcha is required. When I install it, I don’t see the option in the form template for the tag recaptcha. I also don’t see the shortcode to manually place in the form.
when I write the shortcode in the form template [reCAPTCHA], site visitors can see the shortcode not the “I am not a robot”.
Is an API required? I see nowhere a prompt to get the API.

https://cyberscoli.com/join/

thanks,
Nancy