In heath final movie how many actors were used to complete the role he played?

You're likely referring to the film "Heath Ledger" as a role in the movie "The Dark Knight." It is important to remember that Heath Ledger passed away before the release of the movie. Therefore, there was no one else who played the role of the Joker in "The Dark Knight" except for Ledger himself.

All of the scenes with the Joker were filmed before Ledger's death. The filmmakers used various techniques, such as CGI and editing, to complete the film with the footage they had.