JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
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.
You can try to download a fillable PDF of your form where your user can use to fill it up offline and save. Some PDF Readers allow you to save fillable forms such as Adobe Reader.
Then you can just submit the PDF form when there is an internet connection. For more information about fillable PDF forms, you can check this article: How to create a PDF form.