HTML is the language that is used to design web pages. HTML stands for HyperText Markup Language. In HTML, you can design your web page and add content. HTML is a markup language (not a programming language).
This cannot be done alone with HTML.
Backend web development – This includes APIs and web servers. Node.js is the best example here.
Mobile app development – This includes both Android and iOS. React Native is the best example here.
Desktop app development – This includes Windows, OSX, and Linux. Electron.js powers a lot of popular apps – including VS Code, Slack and Discord.
Internet of Things (IoT) – This includes everything from cars to coffee makers, can be powered with Node.js.
Rockets – SpaceX used Chromium for rendering UI on their Dragon Flight mission. So it is very well running outside of Earth as well.