Hello,
There are many exams you can write after inter(class XII) depending upon if you want to go for job or studies and which field in studies.
For jobs you can write following exams

• SSC CHSL
• NDA (3 year training and then join defence forces as officer)
• Air Force X and Y group
• Constable in state police
• Railway NTPL group C and D

For admissions to undergraduate courses the most popular exams are

• JEE Mains and Advance: For engineering courses
• NEET: For medical courses
• BITSAT: for engineering courses in BITS colleges
• Other exams conducted by respective universities

So, choose the exam depending upon your interests and future plans.

Good luck