It is little difficult answering your question as it is a little vague .
There are entrance exmas held at every level .
1) 10+2 level
--> This is level , you can appear for the NDA exam held by UPSE twice an appear . The exam form is available at every
book store by different publications such as - Arihant etc . It is a written paper followed up by a SSB interview .
--> ALso if you have a science stream , yo can apply for the TES entry (Techincal entry ) in which the candiates are
short listed on the basis of their 12th standard percentage . Then there is a direct SSB call (No written paper ) .
2) UES entry (University entry scheme)
This is entry which you can apply in your third (pre final ) year of engineering . There is a Pre-SSB held in the
campass of the college and then the selected candidates are called for the final SSB interview .
3) CDS entry (Combined defense service)
This is another entry at the graduation level . You can apply for this scheme as well but there is a written paper .
If selected , then you are called for the SSB interview .
It is a common for all the branches of defense where all graduates can apply . As the CDSE is a entry for all the three wings of the defence namely
--> IMA (Indian Military Academy) , OTA(Officers Training Academy) , AFA(Air Force Academy) , NA(Naval Academy).
4) TGC entry (Technical Graduate Course)
This is a entry for the engineering candidates who have completed their engineering and appear on the same year of completion that one .
of engineering course .
The age eligibiities for the 10+2 level and the graduation level are different . Which ever suits you , you can apply for
All the best .
Thank you !