Trading with leverage (also known as margin trading) means trading securities by putting down only a percentage of the total value of the position.
Once you have deposited funds into your account, to trade with leverage you'll need to set the level of leverage for each asset class in 'Settings' > 'My accounts' > 'Trading options' > 'Leverage'.
Leveraged trading can give you access to positions of a higher value than the funds in your account. This means that both profits and losses are magnified, making leveraged trading a high-risk endeavour.