An essay is a short written work that focuses on one subject. The thesis statement says what the author is going to write about in his paper. Before the thesis is written, the selection of the subject or topic depends on what kind of essay that is assigned: informative, argumentative, persuasive, comparison/contrast. Let us assume that you are going to write an informative essay. You have chosen the topic, capital punishment.
Remember this is an informative essay, so you are not going to argue for or against the death penalty. Your purpose is to tell the reader about the death penalty. After doing some research on the subject, you decide that you will write about the types of executions, the reasons for using the death penalty, and the cost of using capital punishment.
Now you are ready to write your thesis. This is a sentence(s) that controls the essay. It is tells the exact points that you are going to make in your essay.The thesis is the most important sentence in the essay.
Here is thesis for the subject above. In some countries, Capital punishment is still used for certain crimes. (This is the thesis.)
The types of executions, the reasons for the death penalty, and the cost of capital punishment are three areas that should be examined. (This sentence tells the areas that will be covered in the essay and the order that they will be discussed.
Remember--The thesis is the most important sentence in the essay.