Hello Esakkipandian,

Recruitment is the process that is conducted by companies to fill vacancies that are created in a company or organisation due to various reasons. Recruitment is generally conducted by organisations when they come to college campuses for placements. Recruitment is also conducted by companies off campus or through various placement drives. 

For IT companies in particular, you need to have good command over at least one of the following languages - Java, C, C++ or Python. Also, most of the interview questions are on data structures and algorithm, so these concepts should be very clear.