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 what exactly you want to achieve and if you give us a bit more details we would be able to help you properly.
Now I presume that you want to add/change some validation on a text field. To do that you should:
1. select the textfield widget that you want to change validation for
2. Check the toolbar options and click on Validation
3. select the validation that you would require
Do let us know if this is what you wanted to achieve.