Dear Rakshan

If you belong to general have entered wrong category(ST/SC/OBC/PwD)while filling your application form, there is no chances of changing it but in this case, you don't have to worry about it. If you are not able to produce the caste certificate at the time of counselling, the authority itself is well authorised to consider you as general category and position/ranking of yours will be listed in general category list.

In case of entering the general category but you have ST/SC/OBC/PwD caste certificate, it would be problem for you as may will be considered as general only.

However, you can contact with NTA officials https://www.nta.ac.in/ContactUs

All the best.