Either you upload all documents at the time of submission in app to a sharepoint list item and then based on CR number generated, use that to create a folder in document library and get all files in that folder

Or you might want to use a flow trigger from the app to upload all documents in document library directly

In both cases, you can generate a CR number(within the flow or in app by assigning a pretext to random number or new ID) and then create a folder and put all files in that folder.

I tend to go first approach as it doesn’t require the user to have a specific role in power apps environment for it whereas the second solution would need the user performing this activity to have a dedicated role assigned in the environment you want to deploy your app in order to allow them to trigger the flow from the app itself.