It sounds like you’ve connected to that service using the Dropbox API. You should be able to see it on this page on your account.
If this is the case, then generally, these apps create a private folder on your account which is only accessible to you alone, and can’t be shared to other users.
There may be another implementation with that service so it can be shared to more than one user, though this depends on them. I’d recommend contacting the developer of the app for further assistance on this matter.