Your mortgage lender is the financial institution that loaned you the money. Your mortgage servicer handles the day-to-day tasks of managing your loan. Your loan servicer typically processes your loan payments, responds to borrower inquiries, keeps track of principal and interest paid, manages your escrow account, and may initiate foreclosure if you miss too many loan payments. Your servicer may or may not be the same company that gave you your loan.
TIP: To find out who your servicer is:
Check your monthly mortgage billing statement or payment coupon book