You just have to call the vacancies and ask. Most that accept will advertise the fact, as they are so rare. LA housing laws are tough on a landlord, and section 8 makes them tougher. You may have a very hard time finding a decent place.
Before you ask about the section 8 let them know that you have exceptional credit, references and a long term job. Maybe if they hear your good points they will be more likely to say yes.
As a rule I do not accept section 8, but I have 2 right now. They are section 8 due to disability, not laziness, and I was swayed by their story (which I did verify with the welfare department).
They don't exist. The rental market changes hourly. You have to contact the landlords yourself and ask if they accept Sec 8. Most don't because it's a pain to deal with the federal government and their rules. Especially if you own a nice place where a lot of people want to live./