Bankers often review resumes quickly, so make your strongest evidence easy to find. Your goal is not to describe everything you have done. It is to present a focused argument that you have the academic foundation, relevant experience, attention to detail, and motivation needed for investment banking.
For students and recent graduates, that evidence can come from internships, part-time jobs, student organizations, athletics, academic projects, research, or entrepreneurial work. Prior banking experience helps, but it is not required for every role. A candidate who has never worked at a bank can still demonstrate financial interest, analytical ability, leadership, teamwork, and comfort with demanding responsibilities. That includes ordinary campus work, by the way, when the responsibilities support the point.