You would have to mark it the online application or paper application and you are not required to supply further documentation.
I'd like to ask you another question about the Graduated Repayment Plan. What kinds of loans am I eligible for?
The following loans from the William D. Ford Federal Direct Loan, Direct Loan Program, and the Federal Family Education Loan FFEL Program are eligible for the Graduated Repayment Plan: Direct Subsidized Loans, Direct Unsubsidized Loans, Direct PLUS Loans, Direct Consolidation Loans, Subsidized Federal Stafford Loans, Unsubsidized Federal Stafford Loans, FFEL PLUS Loans, and FFEL Consolidation Loans.
What programs are eligible for the Graduate Payment Plan?