When you ask the question "What is the difference between..." you need to state the two things to which you are comparing differences. Here for example you want to know the difference between career and what? job? A job is an occupation or a role you do to earn money and "make a living." A career is a job too, but it is also a role that someone pursues or studies for a longer time so they qualify for that role. Examples are being a doctor or teacher or police officer. A person CANNOT have a career in these kinds of fields without being trained or without immense training first.