Thank you for the question. The Senate is one of two chambers of the Australian Parliament. The Senate is also referred to as the 'states house' and the 'house of review', names which indicate the important role it plays in our parliament. The main job of the Senate is to make laws (together with the House of Representatives), scrutinise the government to keep it accountable, and to represent the interests of Australia's six states and two territories.
To investigate the role of the Senate in more detail, check out this link.