Post-production occurs in the making of motion pictures, television programs, videos, audio recordings, photography and digital art. It is the general term for all stages of production occurring after the actual end of shooting and/or recording the completed work.
Post-production is in fact many different processes grouped under one name. These typically include:
Typically, the post-production phase of creating a film takes longer than the actual shooting of the film, and can take several months to complete.
Other film production stages include (very broadly) - writing the screenplay, script development (rewriting), financing, pre-production, production and film distribution / marketing.
Major post-production companies with articles on Wikipedia include: