There are two payment types for mortgages - repayment and interest only.
Repayment - this mortgage is when you pay off the capital owed and the interest on that money each month.
With this mortgage type, you will know that you will have paid off your mortgage at the end of your mortgage term.
Interest Only - you only pay the interest on the capital borrowed from the lender.
In this instance, you will not pay off your mortgage at the end of the mortgage term, and you will need to have another repayment vehicle in place when applying for the mortgage, such as savings, an ISA, or plans to sell your property.
However, it is unlikely lenders will allow First-time Buyers to get an interest-only mortgage.