Hii!
You don't need any qualifications as such to become a music composer. But, obviously you should have knowledge of music, notes musical instruments, technicalities, singing, marketing, networking  etc.,
So, for that, besides the basic music learning, you can go for certain certificate and diploma courses such as diploma in Music composition.
The basic eligibility will be passing class 12th with minimum 50% marks in relevant subjects from a recognised board of education.
Hope this helps.
Good luck!