What is the 100MB of file storage of the free plan means?

I am on the free plan. Its says it includes 100mb of data. Is that referring to the data upload for each form submission? 

Yes, that is the File Storage limit of 100MB on the free plan. The file storage is based on the file uploads in your form through the file upload field.

https://www.jotform.com/help/332-How-to-Create-File-Upload-Forms