Hey Marimuthu,
Bachelod of Computer Application (BCA) is a three year course which comprises of six semesters in which the main focus is on learning of Computer Langauges.
Eligibility : Mostly Colleges have criteria to have cleared their 10+2th with 45 % aggregate marks with Maths, but some colleges have relaxation of maths
In BCA you will learn about Computer languages like C, C++, JAVA, etc also software development, computer architecture, operating systems, database management systems, etc
Once you are done with your BCA you can further pursue your MCA or can apply for a job as System Administrator, Junior Programmer, Web Developer, Software Tester,etc
As a fresher you can get a job from a MNC ranging from INR 25000 - INR 40000
Hope it helps :)