Hii pooja

It depends on what kind of problems are there on your admit card. If it is related to your name, your photo or signature then there could be a big problem but if it is related to your date of birth or home address or phone number then that won't create a big problem during the exam. These minor problems could be clarified afterwards when taking admission in any college.

To address the major problems I recommend you to mail at the official email-id of the exam you are giving. Send them a photo or screenshot of your admit card by marking your problem along with a valid proof which justifies your problem. If you get a valid reply to that mail then you can take the print out of that mail along with you in the exam so as to save yourself from any misunderstandings during the exam between you and invigilator. 

If you can't get any as such reply then only thing possible is to take valid id cards along with you as a proof so as to justify your problem to invigilator during the exam but mailing should be your first priority.

All the best!!

Thank you