https://studentaid.gov/help-center/answers/article/report-income-in-the-income-driven-repayment-application
Once you self certify your income, that is valid for 12 months. I imagine the regular rules will be back in place then requiring proof of income.
If you need help understanding your loans, and available options, including how to pay less interest, obtain forgiveness, etc., please reach out to us for a strategy session. And read our review of these sessions, so many people have talked about finally wrapping their heads around their loans and getting some peace of mind knowing there is an end in sight!