Saving Paper docs to existing Dropbox folder structure/file-system.

And to add to what mil6seven6 mentions, you can also export Paper docs to PDF, .docx (Microsoft Word) or even .md (Markdown) by clicking on the ellipsis button on the upper right corner of your Paper docs and then 'Export'. After you're done with exporting the doc in question, you can copy or move the exported file, be it PDF, .docx or .md inside your Dropbox Folder - now living as a normal file among your other Dropbox files. 

I'd also like you to know that our team is always taking into account your feedback when creating the next versions of our apps and services so you can feel free to add your voice to this feature request by upvoting it (simply by clicking on the like button) or even commenting on this thread to provide us with your use-cases as these always help us understand our users' needs and pain-points. 

Thank you all for your continuous feedback and support!