Hi @salvo722!
Any file uploaded as “document” or “attachment” to a Tainacan item will be stored inside your WordPress hosting site. It will live inside the wp-content/uploads/ folder structure, within folders related to the collection Id and then to the item id. You won’t have options to manipulate this.
There are plugins related to offloading media into CDNs like AWS which do this kind of mapping (hosting in another place), but they will work on Tainacan as long as they link the media URL to the expected place in the traditional WordPress folder structure. You can define item “document” or “metadata” as links as well, in this case the file would be stored in another place of you preference. If that link is trully public, the browser will be able to render, for example, an Iframe with a PDF file.
All that said I’m not sure if Tainacan is a good call if you are looking to provide a sort of “customer digital file manager”. We won’t have sub-folder level (while you can replicate that with Taxonomies hierarchy). Our goal is much related to facilitate organizing items with custom metadata and exposing that structured data to the public via blocks such as faceted search.
In any case, if you want to give it a try and have more questions, feel free to reach us in our forum: https://tainacan.discourse.group/. More people there will be willing to help ??