Since version 2.3.6 Droppy allows you to specify multiple upload recipients, these recipients can be set in your admin panel by going to Settings -> Upload settings and then search for the input "Default recipient emails".
You can also add a label for each email so that the email doesn't show up on the upload form, to do this you need to append the label name surrounded by brackets [ ] to the end of each email. Like this:
And that's it, the upload form should automatically show you a dropdown with your recipients. If you only want 1 single recipient then just fill in the single email and all uploads will be sent to that specific email address.