How many exams should I want to complete to apply MBA college? And what are they? Is it necessary to clear all or one of them?

You can go by attempting any one of them. CAT is the widely accepted exam and others are MAT CMAT. There are some institutes specific exams as well, like Symbiosis accepts SNAP, IIFT has IIFT, XLRI has XAT. Though XAT is accepted by other colleges as well. If you are targeting some specific college,