Universities in the United States are secondary education schools designed to help people find their careers. Funding for universities can come from businesses, government, and private donations. Often the universities have to seek funding in addition to the tuition they charge in order to keep running. Universities take a great deal of time and money to run because of the professors, electricity, cafeteria, and basic support required to operate any business.
Universities are just a type of business that is in the business of providing education. They accept students based on academic standing for the most part. There are curriculums that the professors must stick to. Typically a university has undergraduate programs and graduate programs within a variety of disciplines to attract their students.