Upload excel file and populate it with form data

Unfortunately, it's the other way around, wherein you can upload an Excel file to your form and pre-populate form fields from the data found in the Excel file. Here's a guide for that: How-to-Use-the-Spreadsheet-to-Form-Widget 

Also, you can integrate your form with Google Spreadsheet: How-to-Integrate-Form-with-Google-Spreadsheet. So every time a new submission comes in, the data will be sent to the integrated Sheet which you can view online.