What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
Could you please provide us more details of what you would like to accomplish?
You can easily use a check box field just under the "Form Tools" section
You can also see the list of checkbox widgets that you can use, here's the widgets page that you can visit: http://widgets.jotform.com/search/checkbox.
To add a widget, please follow this guide: http://www.jotform.com/help/252-How-to-Add-a-Widget-to-your-Form
I hope that helps. Do let us know if you need more information on this.