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.
Do you mean in the live form? If yes, that's possible by injecting this CSS codes to your form. I have added color on the code below so feel free to remove it if not required.
Here's how to inject it to your form. How-to-Inject-Custom-CSS-Codes
Hope this helps!