Your mortgage is a loan secured against your property, allowing you to purchase your home. In this arrangement, the mortgage lender has the right to take possession of the property and sell it, if you fail to make your mortgage repayments, aiming to recover any losses they may incur.
In exchange for lending you the money, the lender charges you 'interest.' This means that over the mortgage term, you're responsible for paying both the lender's interest and gradually repaying the initial borrowed amount in full before the mortgage concludes.