Single-spaced, a 500-word paper is about one page long. This varies somewhat depending upon the size of font used. In addition, sometimes double-spacing is required in an essay, and this doubles the page length.
A 500-word essay is brief, but it is long enough to include details about facts or opinions. It needs an overarching structure with an introduction, supporting information and a conclusion. The introduction must be compelling to the reader, stimulating his interest. It tells the reader what is to be discussed. The body of the essay is where the writer examines a particular position on the topic that was just introduced. The conclusion summarizes the main points.