sub panel boxes

how many sub panels allowed after a 200 main panel ?
and do they have to be sub-panels rated, or junction boxes allowed

There is no limit as to the number of panels connected to a service. There are limits related to load calculations but it doesn’t sound like that’s what you’re asking. Not sure what you mean about junction boxes.

The number is unlimited. Same goes for junction boxes. If you have a sub-panel it must be wired differently then a main panel with grounds and neutral separate.