Most inmates are required to work. It is built into the structure of daily life, and for good reason on both sides of the fence. Facilities need bodies to keep things running, and inmates who stay busy do easier time.
The range of jobs is broader than most people expect. The kitchen is the biggest operation in any facility and requires constant staffing across multiple shifts, from food prep to serving to cleanup. Orderly crews handle cleaning throughout the unit, the halls, bathrooms, and common areas. Landscaping keeps the grounds maintained. The commissary needs people to stock, sort, and distribute. The chapel, recreation hall, education department, library, and barbershop all rely on inmates to run day-to-day operations with minimal staff oversight.
Some of those assignments do come with a degree of independence. An inmate working in the library or running errands for education is not going to have an officer standing over them every minute. The same goes for certain cleaning assignments that take place outside the immediate cell block. That autonomy is earned over time and tends to go to inmates with clean records who have demonstrated they can be trusted.
Pay is modest, often just a few cents to a dollar or so per hour, but the real value is in the routine. Inmates with jobs move through the day with structure and purpose, which makes the time pass faster and keeps them out of situations that lead to trouble.
If your person is going in, encourage them to get a job assignment as early as possible and take it seriously.