MLA style, which is applicable to any essay genre, provides a system for consistent formatting and for appropriately referencing sources. Regardless of the essay genre, the rules for formatting pages, parenthetical citations and the Works Cited page are the same. MLA calls for double spacing throughout the paper, one inch margins on all sides and a legible 12 point font. Standard MLA formatting also prescribes only one space after punctuation, one inch indention for the first line of each paragraph and a header with the page number in the upper right hand corner of each page.
The expository essay genre, according to the Purdue Online Writing Lab, "requires the student to investigate an idea, evaluate evidence, expound on the idea" and present a clear, concise argument about the idea. Strong expository essays present a clear thesis in the first paragraph, incorporate smooth transitions throughout, provide evidential support and conclude with a more informed consideration of the thesis.
Descriptive essays use concise, vivid language to describe a particular object, emotion, experience or basically any given concept. The purpose of writing this type of essay is to learn to use words creatively and to appeal to the senses of the reader in a way that "clearly forms an impression" of the thing or concept being described, according to Purdue Online Writing Lab.
Narrative essays can either take the form of a story, complete with plot, characters and setting, or as an informational narrative such as a book report. A narrative essay should flow in a logical order, present the point of view of the author or a specific character and incorporate creative writing.
Argumentative essays are similar to expository essays, but are more involved, requiring more extensive research, a solid understanding of opposing points of view and enough evidence collected through research to substantiate the position presented in the essay. Argumentative essays are typically longer than expository essays, requiring at the very least five paragraphs. The basic structure of argumentative essays consists of an introductory paragraph, three evidential body paragraphs and a conclusion, according to Purdue Online Writing Lab.