What does the state POSTPRODUCTION mean?

I assume you are talking about the life cycle state - Post Production. If yes it is one of the life cycle phases defined for a document/an object in your Windchill system. Life cycle phases are used to represent the maturity of the object. It is also used to control who has access to the document and what level of access they have. A more accurate answer for this question can only provide by your business/cad administrator