The thesis statement of an argumentative essay should appear in the introduction.
An argumentative essay is a piece of writing in which the writer presents his/her position on a certain topic as well as evidence and facts to support it. One of the most important parts of the essay is the thesis statement, which presents a claim that states the position of the writer. The thesis statement always appears in the introduction of the essay and it is expressed in one or two sentences. Furthermore, it helps the reader to understand what the essay will be about.