You have to study a course from college first. And then find a garage who willing to take you to learn auto repair for 4 year as apprenticship before you can write a class A mechanic licen.
But the problem is some garage not willing to take you because they worry after you got the licen., you will stole their customer, especially Asian garage.
For some famous car dealer, students who apply to be an apprenticship mechanic in the dealer, the waiting list is over 30 persons waiting, you might need to wait for 6 or 7 years before you can get into the shop.
However, even they hire you, they might hire you as oil change or tire change person, they don't register you into the apprenticship program and you might need to work for the garage for 1 or 2 year before you start learning your auto repaire. Or they only ask you to clean the shop floor and pay you $8 per hour. I see some people even earn as low as $40 a day only.
Remember, if the garage don't register you into the apprenticship program, even you work for the garage for 10 years, you still "NOT" qualify to write the class A licen. exam. You just waste your time to work there.
If you have family, it is hard for you to earn $8 per hours for 4 or 5 year before you can become a mechanic.
BUT after you become a mechanic, you could earn good money, I see some mechanic spend 20 min to repair the car but they charge one hour labour, $60, even they don't need 1 hour time to fix the car. They don't tell the customer they only spent 20 min for the job or they just work slowly or just leave the car in the bay and work on other car until times up.
Simple job but they say it is complicate job and charge a lot from the customer.
Some bad mechanic cheat the customer who know nothing about the car, but the customer though the mechanic is so good to them and even say "Thank you" after they got rape off money.