As of right now, it is only limited to cloud providers such as Box, DropBox, iCloud..etc. Theoretically the "shared files" from a Mac would be in the iCloud Drive folder on a Mac, which would then be visible on iPad or iPhone.
Yeah I know but that's still different than being able to access a library of files over local network, especially for larger files that I don't push to the cloud.
Since 3rd parties are able to make "plug ins" like Dropbox for Files, etc., it seems likely that they'd be able to make one that lets you mount SMB shares like macOS's File Sharing provides.
Does the new Files App in beta 2 recognize USB Flash drives with the Lightning to USB adapter? Have anyone tried to format it in APFS? Thanks for your answer.
I'm sure at some point someone will create a smb file provider app, and then you'll be able to do this easily.