APA is the abbreviation for the American Psychological Association. It is often used to refer to a standard set of rules for writing.
The "Publication Manual of the American Psychological Association" provides detailed information about the rules of writing in APA style. This style is most often used as the standard format for writing and citing sources in papers or articles related to social sciences. It is one of the four most commonly used writing guidelines. Other writing styles that are commonly used include MLA and Chicago.
According to APA guidelines, papers should be written on 8.5 by 11 inch paper. The type should be double-spaced with one-inch margins. The recommended font is 12 point Times New Roman, although any clear, readable font is acceptable. The paper should contain a title page, abstract, main body and references. The APA style guidelines also include rules for citing sources with specific instructions depending upon the type of source.