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.
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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 I understood right you would like users to add options to the answer.
If this is the case maybe you can use the Infinite list widget:
The normal checkbox field also allows an "other" option, but I'm not sure if it is enough for your needs:
But if you share with us more details or the form's url we can take a deeper look to find the best solution for you.
Let us know if we can be of more assistance.