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.
I checked the URL you included on your post http://www.cudeengineers.com/applyonline and the form on that page doesn't appear to be JotForm.
If what you're aiming to do is allow your users/respondents to upload files through a form, then JotForm has that option. And this will work regardless of how your website was built (whether it's powered by Squarespace, Wordpress, etc.)
Here's a short but detailed guide on how to embed a form in Squarespace: Adding-a-form-to-Squarespace
And here's a general guide on how to use the Upload Field: How-to-Create-Upload-Forms
In case you have followup questions, don't hesitate to ask :)