I can't add Captcha on my CRM web form

I can't add Captcha on my CRM web form

I am using the trial version of Zoho CRM, Standard edition. I can see, but cannot add the Captcha field into my Web Form. Both File Upload and Captcha cannot be "grabbed" to bring into the form. I cannot find anywhere in your documentation as to which edition/version I would need to be able to use this field. To date I have received three spam leads (I did not approve them) but I have only had this on my web site since yesterday!

I plan on purchasing a subscription to the Standard edition but if I can't use the Captcha field, it might change my mind about using Zoho's CRM entirely.

Am I missing something? Why can't I use the field? I read in other questions where Zoho states that it is available to use in ALL editions of their CRM product.

Please assist!