You should be careful while applying for any jobs. As you said those details were not mandatory then this should not make any issues later. You can present those documents during the selection process, maybe at that time, you can enclose the documents. Caste certificate is essential if you fall any reservation category otherwise this will not create any issues.
For your satisfaction, you can visit the recruitment company's website and call them to get a better clarification on this. As per my understanding, if any field is not mandatory, will not create any issue during any phase of selection processes.
As you have mentioned in your comment, you have just missed entering the card/certificate number. So, no need to worry about it. Be relaxed and prepare well for other phases of selection processes.
Wish you all the very best.