First, citing your sources helps you avoid plagiarism. It also provides a roadmap for readers to see the sources your arguments are built upon. If you rely on good sources, these citations actually help build the strongest case for your ideas. In the scholarly tradition, citing your sources is a way of continuing a conversation with those who have published before you, agreeing, adding to, or disagreeing with others who have read and thought about your topic.
While there are a few main citation styles (e.g., APA, MLA, Turabian), for this course you'll use the MLA style based on the 8th edition of the MLA style guide.
Always verify with your instructor which citation style you are to follow.