The CAPTCHA field can be added to Inline forms only.
CAPTCHA is a security solution that helps to prevent spam bots from submitting your form. This in turn prevents unwanted, spammy contacts from being added to your account which can harm your deliverability. With CAPTCHA, a contact is required to click on the “I'm not a robot” box when submitting your form. The contact will then need to authenticate themselves by passing a certain test that a machine cannot, such as selecting images that represent an object.
To add a CAPTCHA field to your form, follow these steps:
1. Click on “Forms” from the left navigation menu.
2. Click “Edit” for the form you wish to work with.
3. From the “Fields” section on the Form Editor, click the “Standard” tab.
4. Drag and drop the CAPTCHA into your form.
Here is how the form will behave on the contact's end: