Citations have a standard format so we can easily find the source you're referring to.
Citation styles are specific to certain disciplines. For example, APA Style is used by psychologists, economists, linguists, and sociologists. Just like the information needed to cite a source, we can find all the information we need to access a source in its citation. Though citation styles have different formats, the information contained within them is largely the same. Adhering to a specific citation style shows your audience (and your professor) that you are playing by the rules.