First, you'll need to contact your lender and let them know you want the information. Depending on your lender, you may have to sign in to an online account, call a helpline, or send a formal letter to start the request process.
Ideally, you want your extra payments to go towards the principal amount. However, many lenders will apply the extra payments to any interest accrued since your last payment and then apply anything left over to the principal amount. Other times, lenders may apply extra funds to next month's payment.
Instead, you have to get a 10-day payoff estimate from your current lender, which includes the amount you owe, as well as any interest that might accrue on the principal balance in the next 10 days.