There are so many ways to learn web development, your problem might be how to choose a starting point. The design site CSS-Tricks has their own guide for learning HTML and CSS — but they’ve compiled plenty of alternatives into a wide-ranging but approachable list.
If you prefer to learn from a book, they have two especially good books to recommend. If you want an online course, they have several, with different approaches and interfaces. I was particularly drawn by this description:
Khan Academy has an Intro to HTML/CSS: Making webpages course that’s packaged in a super cool format. It’s like video in that you get to hear the instructor talk you through the learning, but what you see is a real live text editor and real live output. Sometimes the teacher is controlling the code, and then sometimes it breaks for challenges in which you take over and edit the code yourself.
As the guide says, you’ll probably learn by combining more than one method. Writer Chris Coyier compares web development to playing music: You work with a teacher or videos or chord diagrams, but you also play around on your own.
If you think about that too hard, it can start to feel intimidating, so it’s helpful to use a list like this one to pick one starting point and ignore everything else for now. If web development grabs you, you’ll branch out on your own soon enough.
Where Do You Learn HTML & CSS in 2019? | CSS-Tricks