How is that any different that in office? In my experience, in office communication is often MORE difficult to document. Remote communication often happens via email, or text, and can naturally document in an informal way. Technical documents are no harder, or easier, to 'train' employees to create when working remotely or in office.
- Or you could do everything asynchronously to deal with time zones, but then you're introducing an inevitable lag based on overlap of working hours.
This is really more a problem with dispersing your team, than it is with remote working. You can have a remote work company with everyone in the same time zone.
Remote work carries with it a certain number of risks to be sure. But it's not nearly as risky as I feel like people make it out to be.