The role of a bank or mortgage lender is to originate and/or fund loans so that borrowers can buy, build or refinance their home. To originate and fund a loan, the lender must review all financial documentation of the potential borrower, including credit score, assets, debts and debt-to-income ratio, so they can determine if the borrower is qualified for a loan. This is the same basic process, whether the person is buying a family home or refinancing their existing home.