what will be my obc rank and general category rank. If my percentile is 63.6696335 in jee main 2020.please answer me.

Barun, your general category rank will be around 315720. The category specific ranks aren't available yet.
You can check your own rank using your percentile with the formula:
(100-percentile) 869010 100
Here, 869010 is the number of candidates appearing in the examination.

You can predict your possibilities of admission using our College predictor:


Hope this helps!