Mortgage pre-approval helps determine your maximum mortgage amount, estimate monthly payments, and lock in an interest rate for up to 12 months. To obtain it, you need to provide various financial documents. You can get pre-approved through a mortgage broker, who offers multiple options, or directly from a lender, which may limit your choices. Benefits of pre-approval include knowing your borrowing capacity, freezing interest rates, and being seen as a serious buyer. If denied, options include reapplying for a smaller amount or increasing your down payment.