First, a definition of essay writing: an academic paper that is written by a professional author who

First, a definition of essay writing: an academic paper that is written by a professional author who employs the principles of grammar, vocabulary, and style that are usually taught in schools and universities.
The essay writing is a very important part of the academic process. A paper that is written by a professional author who employs the principles of academic writing will be accepted by the university.
Second, technical writing is a separate category from essay writing. I don't consider technical writing as it's not based on academic rules but rather on real-world practical knowledge (in this case in the field of technology) e.g.: How-to guides for Linux or how to hack your phone? It's not about how to write papers but rather how to use software efficiently when using it.
Technical writing is a distinct field of writing where one has to deal with the technical aspects of a given topic. It can be used to write any kind of technical document, from tutorials and manuals to reports and white papers.
Thirdly, there are many differences between technical writers and essay writers or other writers such as journalists/creatives/poets etc., e.g.: There are many aspects which technical writers focus on while others focus more on facts while they can also be classified into different types such as scientist, engineer etc., whereas essays can be categorized into several types (such as personal essays
Technical writers are the ones who are responsible for writing technical content. They write about computer science and software engineering. They write about new technologies and help clients to understand the technology behind a product or service.