The rate, and therefore the payment you lock into and close with, is the rate and payment over the life (or term) of the loan.Fixed rate mortgages are normally fixed for 30, 20, 15 or 10 years. (There are 40 year fixed rate mortgages for particular programs.) With a fixed rate mortgage you pay off both principal and interest each month. The shorter the term, the higher the payment and usually the cheaper the rate. The longer the term, the more interest you pay over the life of the loan but the cheaper the monthly payment. Remember, you are paying mostly interest initially, naturally increasing the portion of the payment that goes towards principal as time goes by.
You can pay the loan off quicker than the initial term by applying more money towards the monthly payment. Pre-payment via auto-deduct payments, biweekly or direct principal payments will drastically reduce the amount of interest as well as the term of the loan. The most common fixed rate mortgage is the 30 year fixed.