Can I only access submissions via JotForm?

Question 3. Can I only access submissions via jotform?

You can view the form submissions in the Submissions page. However, you may integrate your form to Google Spreadsheet, Google Drive, or Dropbox. In this way, the submission will also be forwarded to these 3rd party services. Please take note that the submission will still be in our servers. 

Here are some helpful guides:
How-to-Integrate-Form-with-Google-Spreadsheet
How-to-Integrate-a-Form-with-Google-Drive
Upload-to-Dropbox-with-JotForm

Hope that helps. If you need further assistance, let us know. Thank you.