@akhil
You can only apply for the DGCA exam when they open the application window
The only way to know when the application window will open is to read the DGCA website every day and look for the public announcement
I hope you got the new photo and admit card form uploaded and accepted by the dgca in order to write future DGCA exams ( they sent emails to everyone a month back regarding this )
Please read this CAR thoroughly before going anywhere for a multi endorsement
http://dgca.nic.in/cars/D7B-B18.pdf