Hello,
Yes you can go for any diploma course after graduation.
Diploma are the courses which students opt after 12th and also some course students opt after class 10th the duration of diploma courses are 3 year. And the eligibility criteria for same is to pass the class 12th or 10th with min of 45% .
Some top college are:- Jamia millia islamia , VJTI , MSU baroda , ISBM etc

All the best!!