How do I save only uploads made be user to dropbox?

I do not want all of the form data to be uploaded to dropbox, I just want their attachment uploaded to dropbox. 

I am accumulating their form data into a google sheet. 

If you are using Dropbox integration on your form, it will always include the submission data report and as well as the uploaded file on the form submission.

User guide: Upload-to-Dropbox-with-JotForm

There is no option to cut-off or remove the inclusion of the submission report and capture only the uploaded file.

You can actually use google spreadsheet integration and Dropbox integration simultaneously on the same form.

Hope this help. Let us know how we can be of further assistance.