On-campus – These recruitment drives are organized by a particular institution or university wherein a pre-specified college group is eligible to participate. Under this type, a placement cell primarily arranges the placement drives, and then all eligible candidates related to the pre-decided limited colleges can participate in the selection process. There is not much competition on campus drives, and you need to prepare a test format specific to a particular company.
Off-campus – In the off-campus drive, you can apply and attend the placement events organized by some MNCs and, at times, by colleges. You must be eligible to participate in the drive, regardless of which college you belong to, and thus, candidates who fulfill the eligibility criteria can partake in these events. Moreover, companies also get an opportunity to select suitable candidates. So, there is a difference in the level of competition between the two recruitment drives, with off-campus being highly competitive because the number of participants is more than on-campus.