The thesis is a statement of the paper's purpose; it therefore drives every paragraph of the essay.
A thesis statement is a single sentence. It must be a statement of fact or opinion, not a question.
Writers commonly place the thesis statement at the end of the first paragraph. Less commonly, the thesis statement can be the first sentence of the first paragraph or even a stand-alone sentence.
Besides its location, the thesis can be identified by its clear statement of the essay's purpose.
A thesis provides the reader with a controlling idea that places the rest of the essay in context. In addition, a thesis also helps the writer to compose and revise the essay.
Writers must be aware of the thesis as they compose and revise their essays. Ideas not related to the thesis need to be kept out of the essay; or, the thesis may need to be revised to encompass them.