PHP is a server side language that is used to make dynamic websites. Most of the world's websites are dynamic, meaning they change.
This course expects that you know some basic HTML and have some understanding of how web technologies including servers work.
The use of HTML in these course is minimal, but a large part of PHP is being able to view the results of it and HTML is the way to do this.
You can find my HTML course here.
Finally, this course was recognised by Udemy on 25th September 2015, something I am very proud of. You can view their courses here.