Saving to iCloud Drive?

Let me be clear that I understand iCloud sync is not possible and that is not what I’m referring to.

I backup my Mac to iCloud Drive so the actual file that I open on my Mac is out there on iCloud Drive and can be opened on the phone. Is there a way to open (and override) that file on iOS? It is the same file that is opened on the Mac. I think this should be possible even if the feature is not yet implemented.

See this thread for a discussion on possibilities: