* You may have signed a contract with the production company directly. This is most common for actors with major roles in films, who negotiate their contracts with the production company's casting department. The contract will specify the amount of your payment and the terms of your employment, such as your start and end dates.
* You may have been hired through a non-union casting agency. Non-union casting agencies typically work with smaller productions and independent film companies that don't have their own casting department. These agencies may charge a fee to actors, but they will also negotiate your payment and terms of employment with the production company.
* You may have been paid as a "stand-in" or "extra." Stand-ins are used to mark actors' positions on set, while extras appear in crowd scenes. These roles are typically paid at a lower rate than speaking roles, and you may not receive a contract.
If you're not sure whether you'll get paid if you're in a film without an agent, it's best to ask the casting director or production company. They will be able to provide you with information about your payment and the terms of your employment.