Codecademy: Find some free courses to get you started with coding. They have resources for a variety of languages, such as Python, Ruby, Java, HTML, and more! (Note: The beginner courses are free. If you want to continue, you'll have to sign up for the Pro Plan, which costs money.)
SoloLearn: SoloLearn offers free courses to get you started with coding in thirteen different languages, including Python, C++, Ruby, HTML, Java, and more! You can download their app to your phone, so you can code while you're on the go as well.
Repl.it: Awesome online IDE for a wide variety of languages, including Python, Ruby, Java, HTML, C++, and more. You can save and execute your code with their online editor.