See if you have the option to upload ews during the registration of your counselling then you won't be able to upload it if the registration is done. Now if you are not asked for the EWS certificate during the counselling, then you have nothing to worry about. New notifications will be released by the organizing departments and then you have to submit the certificate either on the portal or to the college you have taken admission in.

Although you didn't mentioned the name of the examination, I just mentioned here a general scenario.

I hope this answer helps. All the very best for your future endeavors!