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.
May I ask what kind of file you're planning to upload? We have an app called Spread2Jot that allows you to upload PDF or Excel forms to an online form. Here's the link: https://www.jotform.com/spread2jot/.
If you want to convert an online form to become an fillable PDF form, please refer to this guide: https://www.jotform.com/help/212-How-to-create-a-PDF-form
Hope that helps. Thank you.