Mona, EWS reservation is for General Category students whose annual income from all sources is less than 8 lakhs per annum. If you belong to General Category and do not avail any reservation benefits of OBC, SC,ST, then you are eligible for EWS quota. For this you need to get an income certificate done by your local Tehsildar. If you have already made a correction once to your application form, you may not be able to make changes again because the correction window is just a one time opportunity.