From DMJ Productions

A film producer is a person who oversees film production. Either employed by a production company or working independently, producers plan and coordinate various aspects of film production, such as selecting the script, coordinating writing, directing, editing, and arranging financing.

The producer is responsible for finding and selecting promising material for development. Unless the film is based on an existing script, the producer hires a screenwriter and oversees the script's development. These activities culminate with the pitch, led by the producer, to secure the financial backing that enables production to begin.

From Wikipedia