You do not need an agent, a drama-school degree, or a move to Hollywood to appear in a movie or television show. Background acting, commonly called extra work, is one of the most accessible ways to experience a professional set while earning money.
Productions regularly need ordinary-looking people to fill restaurants, offices, hospitals, stadiums, streets, and party scenes. If you want to become a movie extra, the bigger challenge is knowing where legitimate opportunities are posted and what casting teams expect once you are hired.