Migration certificate is a document issued by the concerned board/university one studies. It is issued at the completion of the course along with other necessary documents and is necessary for admission for the next course. It is like a relieving order from the college/institution for you to continue studies further in institutions other than your current institution.
I am sure you must have got migration certificate from your school after class 10, and class 12 and from the university if you have completed graduation.
Important: University Is Charging Fees For Applying Migration Certificate In India.