Your lecturers will expect you to use a wide range of academic sources in your coursework. When we refer to academic sources, we mean those which have been written by academic experts and researchers, based on their scholarly research and knowledge. Generally these will be academic books and scholarly journal articles. But, depending on your subject, you may need other sources such as law cases, policy documents, images, maps, statistics.
By using academic sources, you are demonstrating your ability to read and engage with the scholarly literature in your subject. You should use the information that you find to provide evidence for your arguments and to demonstrate the solid knowledge of the topic that you have developed from your reading.
Other non-academic sources may also be useful for helping you develop your ideas and to gather information about current issues and developments.