Dear Aritra Sen,I think you are asking about the difference in higher studies and placement.So,i would say that placement is the job that you get during your placement session in your college.Higher studies are like Mtech.,Phd etc. done to work as Professor in Engineering colleges,Join good firms in Research and development etc.Only go towards higher studies if you are interested and want some specialisation in your field.Placement is the job opportunity you have just in your final year.

Hope this helps.