apa-style should be used for any questions related to formatting bibliographies and citations using the American Psychological Association style, or styles derived from it. There are two main packages that implement the APA style, depending on the bibliography package used:
In addition to the APA bibliography style, there are also document classes that implement some version of the APA article format. If you have questions about these packages, you should add the package name specifically as a tag.
Classes that implement the APA article format