“Campus” is not restricted to universities and colleges. It can be used for high schools, corporations, institutes etc. There are regional differences in the use of “college” and “university”. In the US, we would say someone is “going to college” regardless of whether the establishment attended had an official name of “university” “college” “institute” etc.

In our cities , here are many colleges and universities. Both are educational institution. Both are offering under graduate and post graduate courses, even few colleges offering M.Phil, and PhD . But most of the college under in university. College offering under graduate degree also. Both has campus, that means , areas of the institute. May be there are available , hostel, canteen, play ground, swimming pool. But in university there are more facilities are available other than colleges. university can handle exam , college depend on the university for exam , results, there are lot of office incharge.

campus is the actual physical location - the buildings, the dorms, the libraries are all part of the campus. the difference between college and university is a difficult questions, my understandings is that a college usually offers only an undergraduate degree (so Harvard college is an example) while a university also offers graduate programs leading to master's or doctoral degrees. A university is usually made up of many colleges. Again, this is my understanding so not sure it is definitely right.