Hello. The exam to be written depends upon the quality of the b-school,you are applying for.

For top b-schools and ivy League b-schools, GMAT is a must. Along with it, you must have IELTS or TOEFL in order to prove your language proficiency.

For some good b-schools, only GRE  and IELTS is required.

And then there are few b-schools, which requires only IELTS.

Hope this helps.

All the best.

Hii Senthamil
You are interested to pursue your career in Master in Business Management in foreign universities. For this you can go for two entrance examination like Graduate Record Examination and Global Management admission test. Previously GRE was famous for the MS applicant while GMAT was for MBA aspirants. But now a days you can opt any one of the above to study in foreign universities. Apart from this your strong profile will help you in fetching a good foreign university.