my general ews certificate is made on 14-07-2020 . till which date is it valid? ( for jee mains) 2021
As you mentioned that you have made your EWS certificate on the 14/07/2020. Now for the current year this is simply waste. Make a new recent EWS certificate because jee would ask for the current year and they won't accept your EWS certificate even if it is valid till the date.
The most important thing which comes into account for or certificate verification of reservation categories is the the legitimacy of the certificate and its valid time period.
The caste certificate is generally valid for at least three months from its date of renewal, considering the case of the JEE Mains examination.
All the best.