A mortgage is a legal loan agreement using the home as collateral, typically repaid over 15 or 30 years with monthly payments covering principal, interest, taxes, and insurance. Types include fixed-rate, adjustable-rate, and government-backed loans. Interest accrues mostly early on, and extra principal payments can save money. Rates depend on market and personal factors like credit score and down payment. Missing payments can lead to late fees, credit damage, or foreclosure, but options exist for hardship.