There are a variety of ways to learn HTML online. For example, many websites offer free video tutorials and lessons you can take to help you learn. Out of all of the options, I think W3Schools is a great choice for beginners to learn HTML and CSS.
The interactive lessons and tutorials explain everything in easy terms, which makes it perfect for beginners with little to no knowledge of HTML. W3Schools also lets you play with HTML on the site to see what effects it will make on a mock webpage. It’s fun and simple to use. This video shows you how to get started with W3Schools, so check it out!
You can take a look at some of the other options for learning HTML here as well.
For some, it might be easier to learn web design online. The web design class I am currently taking (CA 260) is a blended course, meaning it is taught partially in a classroom and partially online.
I personally like blended courses better than fully online courses. I think being able to ask my professor questions and have them help me with solutions in person is easier than having to figure it out on my own. Web design as a subject can be fairly difficult for some people to grasp without someone physically there to show them what they are doing wrong.
Massive open online courses (MOOCs) work for some students, but the majority need additional instruction from a professor in order to learn what they are meant to learn from a course. This article has more information on MOOCs, so read and judge for yourself whether or not MOOCs work.