freeCodeCamp
This is the place that I started and fell in love with coding! Start here if you want to learn HTML and CSS. Make sure to put your own creative twist on the module projects, you will learn so much more!
Main resource - learn by doing - Challenges - Free certification
Scrimba
The courses are in a screen sharing format, and offer challenges that you can solve. There are many mini projects and is taught in bite-sized pieces. Go here if you are an auditory or visual learner. Love this.
Interactive - video content - Unique screen share interface
Coder Coder
Awesome YouTube channel with walkthrough projects. She explains every piece of code that is written, and breaks it down for beginners. She also has a great video explaining VS code, git and github.
Walkthrough videos - step-by-step instruction - github for beginners
W3Schools
Great for reference and refreshing knowledge. Mini quizzes and problems to solve and get points. Extensive information and short pieces of example code. Would use in addition to your main resource.
Structured learning path - Organized reference material
Mimo
Great for practice on the go! Also has a leaderboard so it can be fun to compete. Can do a free trial and try to finish the HTML/CSS courses.
Sololearn
Similar to Mimo, review what you have learned so it sticks in your brain.
100Devs
Includes HTML, CSS and JavaScript in the curriculum. Can join a community or go through the videos on YouTube. For people who like video based learning. Have not used this much. Link: 100Devs site
Community - Reasoning behind the code