Does an essay have to be 5 paragraphs with a conclusion?

No, an essay does not have to be 5 paragraphs with a conclusion. The 5-paragraph essay is a common structure taught in introductory writing classes, but it's a simplified model. Essays can be—and often are—much longer and more complex, with more than five paragraphs and a more nuanced conclusion. The length and structure of an essay depend entirely on the topic, the assignment's requirements, and the writer's argument.