As far as I have used and seen, there is no folder structure. Wouldn’t it be nice to create folders in the document upload fields?
Can you elaborate on that? I’m not sure I understand - where do you want to see a folder structure?
To express it more clearly, creating a folder in the Files area inside the created channels.
Simple “Folder” / Similar programs has that future. Imagine that you can create a folder. 
- Permission to access folder
- See who created the folder
- Allowing who has access
The “files area” inside a channel is just a search result of all files posted in the channel, it’s not a way to organize the files since the’re attached to the posts in the channel and therefore cannot be grouped together or put into folders per channel. The search result might also contain files from different channels, depending on the search query, so I think you’re maybe confusing the search results view here with some kind of a filesystem where you can organize uploaded files.
You are right about this, but if we talk about the chat area, I think it is debatable how correct the created structure is. I think that the chat area is a structure that works with the logic of Whatsapp, which is already successful enough in this regard. In an area where hundreds of documents are shared, nothing has been thought about document archiving.
For example, in a channel with 30 people, you cannot share a document that you want 15 people to see. You have to go and create a group and do that. This brings to mind the WhatsApp application. Of course, the application is not limited to this, but when the whole structure is built on the chat area, we are looking for a little more detail.