to explain how things happen
The purpose of one kind of process essay, is to explain how to do something.
In the thesis at the beginning of the essay
The purpose of the lead in a process essay is to introduce the topic and grab the reader's attention. It should provide an overview of the process being described and create interest in the steps that will be outlined in the essay.
The purpose of an expository essay is to explain a topic. The essay can be an explanation about a demonstration, lecture, to clarify a process or to instruct a reader on how to do something.
To explore an idea (apex)
In the thesis apex
purpose; audience
A persuasive essay is an essay used to convince a reader about a particular idea, usually one that writer believe in, which is the main purpose of a persuasive essay.
tone
tone
process
to provide several possible answers to one question.