I am from general category, is it important for me to attach my caste certificate with my MCA entrance test form?

No, University or College commonly asks for such a certificate. So there must not be any need to. Make and send one such certificate. Besides, you can only make an affidavit or a verification certificate that your are in General caste. Actual purpose of a Caste Certificate is to claim Reservation.

What for? General caste people do not have to submit any certificate.