Hello Anchal ,

As you have completed your BBA degree you can do your masters in the fashion designing and merchandising .  This will give you a great career opportunities not only India but also in the foreign countries.   As you want to take in admission for the NIFT you need to give an entrance examination which is conducted by NIFT and after clearing the NIFT entrance exam you can take and admission for the master degree.   You can also apply to other colleges which offer fashion designing courses in India.  You can apply to INIFD, pearl institute , DSK  design school, Dristi college etc.  For this colleges you need to given entrance examination conducted by the respective colleges.

Hope It Helps

All The Best !!!