For all of these types of work, the SAG-AFTRA, the union for actors, can be associated with the production. When a producer starts a production, he can register it with SAG-AFTRA to become a “union” production. The project is assigned a contract based on a budget of the production, and the production must follow the terms of the union contract.
For nearly every type of production, there is an associated contract. Typically, bigger productions are nearly all union productions. Actors typically prefer union acting jobs because they offer higher pay than non-union jobs. Also, there are guaranteed break times, warm meals, better trailers and facilities, and production insurance production. Also, with the Coronavirus COVID-19 pandemic, there are COVID-19 safety protocols productions must follow.
If a project is a non-union production, producers do not have to pay, feed, house, or give actors breaks. You are essentially a freelance, and there is no authority to contact if something goes wrong. That said, your agent, manager, can negotiate a contract to make sure those benefits are tied to your job
What does this mean for producers and filmmakers? Once you have an actor on your project who is SAG, you must now follow all SAG requirements including obtaining production insurance, workers compensation, Minimum Sag wage based on project size and other tons of SAG paperwork. There are few exceptions, like members who are FI-CO
Financial core (also known as FiCore or Fi–Core) refers to a legal agreement, which allows for actors to work on non union production without making the projects a union project. If you want to know more about SAG, a lot is available to read up on their website.