For example, if you are writing an essay about the theory of evolution, introduce the topic broadly in the introduction, go into detail about the theory based on your research in the body paragraphs and then summarize your findings in the conclusion.
Even if the essay you are writing is a persuasive piece -- one in which you try to convince the reader of your stance on an issue -- you still have to back up your arguments with researched facts.
It is instead a carefree and conventional method of writing.
It addresses directly to the audience by the use of colloquial words and expressions (guy, kiddo, superb, etc.), clichés (loads of, use many, etc.), abbreviated words (TV, ASAP, etc.) and second person pronoun (you, your, etc.).
Formal writing is explicitly stated and appears in the first or second paragraph of the essay.
Informal writing is not stated explicitly and is likely to appear anywhere in an article.
Formal writing adopts a complex sentence structure.
Informal writing takes a simple sentence structure.
In contrast, informal essays, also known as personal essays, can be written in the first-person voice and tend to be subjective and opinion based.
A formal essay is heavily structured; it includes cited research, has a clear introduction, body and conclusion and supports a stated thesis.