What is a movie that takes place prior to another movie?

Can you elaborate on the concept of a movie that serves as a prequel to another film? How does it differ from a sequel or a standalone movie? Are there any notable examples of prequel movies that have successfully built upon the existing lore of their predecessor, while also offering a unique and engaging narrative experience for audiences? What factors do filmmakers consider when deciding whether to create a prequel, and how do they ensure that it complements the original film without detracting from its impact?