When I scan or import a new document, Paperwork creates a folder with the files needed to handle the document. My question is: Can I put other files manually into that folder without disturbing Paperwork? Example: I have bank account statements as PDF that I have imported, but I want to have the CSV version (and later maybe worked over as ODS) at the same place. Obviously, there are naming conventions that I should not mess up, but could there be any other problem?
Yes, you can. Paperwork scans the directory each time it starts and take into account any changes. Unknown files are just ignored.
The file structure expected by Paperwork is described here: Work directory organization · Wiki · World / OpenPaperwork / paperwork · GitLab