Unlike university programs, trades and apprenticeships do not have "majors" as such. Rather, your choice of trade determines the courses you will take, and there are also a variety of specializations within individual trades that you can consider. These specializations can also affect the kinds of courses you take and the kind of work experience you will gain while studying. For example, ironworkers can choose between reinforcing or structural/ ornamental options, and within welding you can choose to specialize in electric arc welding, MIG welding, acetylene gas welding, heli-arc TIG welding, and more. Be sure to research the trade that interests you to see what specialization options there may be.