Each area of study has its own citation style.  Always check with your professor or instructor about which one you should use in your classes.  The two most widely used citation styles are the APA  (American Psychological Association) for the Social Science, and the MLA (Modern Language Association) for the Humanities.  The sciences have a variety of styles.  See this page for a list:  https://libguides.asu.edu/citing/MoreStyles.