A captcha can help keep unwanted spam and bots away from you site. This tutorials shows how to add a very simple but affective captcha checkbox.
Step 1: Add A Contact Form Element
First drag a contact form to your designated area and click on it to edit it. You can add up to 4 features of whatever you want, then add a "Checkbox".
Step 2: Edit The Checkbox
After you do that you click on "Option Items" and then click on "Edit". Once you click on "Edit" some minus buttons will appear and click on all of them except for one. Name that last one "I am not a robot" and click done. After that click publish.
You Are Done! Enjoy Your New Captcha Checkbox!