One more tip: if your read how to write an expository essay but still feel wobbly and insecure, let us do the trick for you.
Instead, try to provide some basic definition of the matter you discuss and add some crucial details about it that creates causal, explanatory or contrasting effect.
For example, ‘a so and so disease is a disease that does this and this to patients thus confining them to bed for a long time, yet the cure for it is still to be found’.
It will also highlight why you speak of this topic and why it matters.
Main body will include all the important points that you have jotted down (or copy-pasted to your draft).
Other title elements (your name, the course name, teacher's name and the due date...) may be double or single-spaced and may be either centered or left aligned in the final third of your title page.
Unless otherwise specified, essay text is left aligned.
The first page of text is page 1 and may be numbered at the bottom center, in the upper right hand corner, or left unnumbered. 3" or indicators like "page 2 of 5" are usually inappropriate for essays.
Number subsequent pages in the upper right hand corner of each page. In the MLA style, the page number is preceded by your last name spaces, i.e. Also in the MLA style all pages that contain the essay text are numbered in the upper right hand corner.
Most probably your essay should be no more that 3-5 pages according to your instructor’s guidelines. As you have shaped understanding of the topic and created a kind of draft, you can start writing.
Writing an expository essay is the same as writing any typical 5-paragrah essay.