Do you apply job earlier before you graduate or after you had graduate? Which one do you prefer & why?

I think if you know that you are graduating definitely look for a job before you graduate. That is if you want to work directly after graduating, so that you can start immediately and get a head start in the job market. If you want to take a break, maybe start looking after you graduate, when you are prepared to start work. If you do apply before you graduate and get a job you can maybe ask to defer starting work.

A friend of mine applied in her last year of her degree and went for an interview before she graduated. She asked to start six months after her graduation because she wanted a break.

I got a job a loong time before I graduated, I still have not finished college. I had an urge to eat at least once a day.
Before you graduate would be considered an internship.