Whether for internships or full-time jobs, there are typically two different paths MBAs follow in recruitment - structured recruitment and direct hire recruitment.
Companies who want an ongoing, existing pipeline of MBAs have structured leadership/associate/general management programmes. Because they can plan ahead for their business needs, these roles tend to be more visible and competitive. The route to getting a structured internship is more predictable but the timing is less flexible.
Students may also pursue direct hire recruitment. These are roles offered throughout the year when a business need arises. Some are advertised and in addition there are many “hidden” or unadvertised opportunities. They are driven by your networking efforts and offer more flexibility as recruitment happens closer to the actual start date.