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.
I am not sure if I have understood your question correctly. Do you want to add Open Sans Light fonts in your form?
Open Sans Light seems to be a google gont and it is possible to use it. The following guide should help you: http://www.jotform.com/help/100-How-to-Use-Google-Fonts-in-your-Form
Hope this helps.
Do get back to us if you have any questions.