Restrict form entries by enabling CAPTCHA

Refer to  this  page to learn about Captcha validation for Forms

1. Open the form builder.
   
2. Click the  Properties  icon in the top-right of the form builder, as shown below. The  Form Properties  pane will appear on the right.
   

   

3. Navigate to the  Form Properties  > Restrict Form Entries  section.
4. Check the checkbox next to  Enable Captcha :
   

   
   

5. In the live mode of the application, the Captcha will appear as seen below.
   

6. The form cannot be submitted unless the Captcha is entered.