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.
Are you a registered user or under the same guest account? I would suggest that you register an account and either try out the free plan and go on upgrade if you find the form useful, this will let you use the form builder fully.
To answer your question, you can find more information about the upload file size limit here http://www.jotform.com/help/33-Changing-the-Upload-Size-Limit. You can also find a guide about multiple file upload here, http://www.jotform.com/help/29-Upload-Field-Allowed-File-Types.
I hope this helps. Let us know if you need further assistance.