Introductory Paragraph - this is the first paragraph in an essay that essentially "introduces" the subject and the author's stand on that subject. Included in this paragraph are necessary background information, the subject and some key information about the subject (or topic) of the essay, and the stand the author of the essay plans to take on in the essay.
Body Paragraph - a paragraph (usually one of many) within an essay that follows the introduction and takes on the role of developing a main point of the essay after it is introduced in the introductory paragraph.
Descriptive Essay - an essay that essentially attempts to offer a detailed description of a subject or topic.
Narrative Essay - an essay that takes on a "narrative" tone, telling a story of some experience or event.
Argumentative Essay - an essay that attempts to argue a chosen side on a debatable topic.
Introductory Paragraph sets the tone by stating the main topic of the essay in a topic sentence and hinting at the writer's stance on the topic. It may include an anecdote, quotation or background information to lightly highlight the topic to the readers.
Body Paragraph usually three or more, gives supporting details to the topic put forward in the introduction.
Descriptive Essay expresses the characteristics of an object such as what it looks like, the sounds it makes, and what it feels, smells and tastes like. It appeals to the five senses of the reader through the use of literary devices: imagery, comparison and spacial words.
Narrative Essay seeks to present an event to the reader as if they were there witnessing the incident. In order to check if an article is a narrative one should be able to answer the following: how, what, where, when, who. Essentially one should be able to recount what happened at a particular event. It uses devices such as transitional words/phrases, definition, cause and effect and examples.
Persuasive/Argumentative Essay is an attempt to convince or persuade a reader that a particular topic/subject is true by means of appeal to reason or emotion. In order to check if an article is argumentative one should be able to cite evidence from the essay.