Nothing to worry, you can apply on behalf of your parents that income certificate will cover you as well if you are applying something that needs income certificate as a proof of income or you can apply your income certificate directly from your centre Deputy Commisioner’s sub division office. When I was student I have no income but when I apply for competitive exam or getting admission to college or applying for passport they ask me to submit income certificate, so I went to the sub division office of deputy commissioner and get income certificate by submitting name, address and purpose along with a fees of Rupees 50.00.

I hope you got the answer.