Here are the good steps on How to find student loan account number
How do I find out information about my student loans?
You can find information about your student loans, including your balance, through the National Student Loan Data System for federal loans, or through your student loan servicer for private loans.
Federal Student Loans
The definitive source for information on your federal student loans is the NSLDS is the U.S. Department of Education’s central database for student aid. NSLDS receives data from schools, the federal loan programs, and other U.S. Department of Education programs. NSLDS also provides a centralized, integrated view of your federal student loans and grants so you can access and inquire about them.
To find out information on your private student loans, you’ll need to contact each of your private student loan servicers to determine your total loan balance or check your credit report.
Unlike federal student loans, there is not a single website that contains information about all of your private student loans. Your private student loans will not be listed in NSLDS because the system shows only your federal student loans, not your private student loans.
If you do not know about private student loans you might have, request a free credit report atPrivate student lenders may report your loans to credit reporting agencies even while you’re still in school or in deferment.