The APA style of documentation refers to the rules and requirements described by the American Psychological Association while documenting research papers or dissertations in subjects such as social sciences and arts. Writing an APA style essay refers to writing it and formatting it according to the APA norms and guidelines. This kind of style is used for writing term papers, case studies, literature reviews and research reports. When you format your essay according to the APA style, you will need to adhere to rules around typeface, line spacing, margins, page headers, footers etc. Here are some guidelines around writing an APA style essay.