title: How do I add a CAPTCHA to my PHP form?
body: <p>My knowledge of php is not good and I need help. </p>
  
  <p>I have this <a href="http://phpforms.net/php-forms.html" rel="noreferrer">php form</a> but I don't know how to add a CAPTCHA mechanism.</p>
  
  <p>How do I achieve this?</p>