An essay can tell a story and be descriptive, but there's no escape from the hard and fast rules around structuring an essay. Creative writing, on the other hand, is where essay writers go to truly let their hair down. While an essay can be creatively written, creative writing is the place where the poets and storytellers really shine.
Essays can be expository, narrative, persuasive, or descriptive, but even with this wide range of possibilities, each type has its own specific structuring requirements. The most important rule of any good essay, and the reason for all the structuring, is clarity. Can the readers of your essay easily understand what idea you're presenting or what story you're telling? Does the writing flow along a logical path in which one sentence leads into the next and thoughts transition naturally? If so, you're on your way to an excellent essay.
Essays generally stick to a specific topic or thesis statement. Body paragraphs include topic sentences that flesh out the thesis statement or further tell a narrative story. A conclusion paragraph sums up the ideas and makes inferences about them. Narrative essays are often written in first person, but most essays are written in third person.
In creative writing, the sky is the limit. This type of writing can include poetry that is precisely structured as a haiku or limerick, but can also be a short story, a memoir, or a narrative essay. Some forms of creative writing are written in first person, some in second, and some in third. The freedom to be expressive and convey emotions is most strongly felt in the many forms of creative writing.
Creative writing is a wide umbrella under which an endless amount of ideas can be expressed using any writing type or structure imaginable.
The purpose of any good essay is to inform readers while the purpose of creative writing is to inspire, to weave language creatively, to invoke an emotion or response, or to just express ideas and thoughts. While a narrative essay may include some descriptive writing, most essays lean more toward the academic than the poetic.
If you like to research a topic and then impart the knowledge you gained during that research to others, essay writing is for you. When you'd rather tell a ghost story, or write a poem about your cheating ex-boyfriend, or if you decide you're ready to write your autobiography, get ready to do some creative writing.