Put in the simplest terms, a mortgage loan gives you the money to enable you to purchase a property. Buying property is probably the biggest financial commitment most of us will ever make and most people don't have the necessary funds available to buy a house or condominium outright, which is where a mortgage loan come in. A mortgage allows you to borrow thousands of dollars at a relatively low rate of interest in comparison with other forms of borrowing.
The loan terms (or length time in which the loan needs to be paid) can vary quite a lot. Most people take out mortgages with loan terms of around 15 or 30 years, and it's quite common to find that monthly mortgage repayments are substantially lower than the amount that would be charged if you were to rent.