With a fixed rate mortgage the interest rate is fixed for the life of the loan.
Pre-qualification: You have given the mortgage loan officer your financial information and based on the stated income and debts, the loan officer gives you the amount of mortgage you will qualify for. Generally, no credit is checked, no income or assets are verified
Pre-approval: Your income, credit and assets are verified and submitted to an underwriter for approval. The loan officer will issue a “pre-approval letter” that will allow you to shop for homes and make an offer. Many realtors require you be pre-approved before you start shopping for a home.