There are a variety of jobs: full time, part time, temporary, odd jobs, seasonal, self-employment.
People may have a chosen occupation for which they have received training or a degree.
Those who do not hold down a steady job may do odd jobs or be unemployed.
Moonlighting is the practice of holding an additional job or jobs, often at night, in addition to one’s main job, usually to earn extra income. A person who moonlights may have little time left for sleep or leisure activities.