Dear Arul,
You are eligible to apply for B.Ed after your graduation degree. The eligibility criteria for B.Ed is that you should have minimum of 45% marks in your qualifying exam, and you should be at least 19 years of age (most universities do not have a maximum age limit). Admission criteria to B.Ed courses varies, however most universities admit candidates based on a Common Entrance Test. If you are interested in teaching Secondary and Senior Secondary classes, then you might also want to get a post graduate degree either before or after the B.Ed. For most of the universities an admission to the B.Ed program requires a Bachelor’s degree or a higher degree from a recognized University, and In-service teachers with two years full time teaching experience on temporary/permanent basis as Primary/Graduate/Post Graduate teacher in a primary/secondary/higher/senior secondary school recognized by the Central or State Government or a Union Territory.