How to upload submissions from an excel spreadsheet?

I'd like to quickly edit approximately 50 submissions on my JotForm.  I thought I'd download them to excel, then edit and re-upload. 

Can I do this?  If yes, how?

You can upload/import submission from an excel or csv file by using the Import App of JotForm. You can check this guide for more information: Import App Easily Import Your Excel or CSV Data into JotForm.

Do let us know if you need further assistance.