A verification code is a security protection method used by form owners to avoid Internet robots from abusing and spamming their forms.
There are different verification code types, but the most commonly used is CAPTCHA. This generates a random code within an image next to a text box. The form visitor has to type in the exact code in order for the form data to be sent.
Owners can deactivate the verification code of their web forms. However, this would increase the vulnerability of the forms to spamming attacks.
We encourage our form builder users to use verification codes whenever possible on their forms. You can find them in the Security section of the Form Editor, under Captcha settings.