For freshers, there is no perpetual hiring in any company, unlike it happens for experienced folks. Whenever it happens, it happens like a group hiring, like a pool campus hiring drive. Big MNCs usually send mass emails to employees about such off-campus hiring, and ask them to refer or upload resume of freshers, for some specific date scheduled hiring plans (Like upload by x date, combined written test on y date etc.) So you should just stay connected with seniors of various big MNCs, and should have put up a request to them that you be informed about any such hiring round. Good Luck.