It's not at all necessary. First of all, GMAT is an exam which is mainly conducted across the world to pursue your MBA degree from the foreign b-schools. In India top, most Indian School of Business (ISB), Hyderabad, is the one which gives admission to students only on the basis of GMAT examination score.

Some of the private colleges in India also accept GMAT score along with other MBA exam scores like CAT, MAT, CMAT, XAT etc. to give admission in their college.

But there is no relation to GMAT exam and digital marketing. It totally depends on the college curriculum whether it provides courses or stream of Digital Marketing or not.

Delete this myth from your mind and explore the college before reaching any conclusion.

All the best!!