There are many different essay forms that might be acceptable or expected for a specific assignment. Clarify any uncertainties about your instructor’s expectations as early as possible.
Common in North American universities is the general three-part persuasive form known as the Anglo-American Essay Form. An essay following this form repeats its main ideas three times with different degrees of depth and length: once in an introduction; again in the body; and finally in the conclusion.
An introduction tells your reader what they should expect the essay to discuss (the topic), how the discussion will proceed (a road map for what’s to come) and what conclusion you will reach (often in the form of a thesis statement).
The body of the essay contains the detailed presentation and discussion (analysis) of information, evidence, models, alternatives and reasons for the positions you or the authors being considered are taking.
A conclusion reminds your reader of the most important points of discussion and analysis, and comes to a decision (or decisions) about them.