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.
If you're using radio buttons option:
That is not possible, those buttons are meant to be used in 'select only one option at the time'.
But if you use the Check-Box option you will be able to select multiple options at the time:
If you would like to have Select All option in checkbox field you can use Select All Widget, which looks like this:
Hope this helps.
If you have any further questions please let us know.