The task board provides a list of available tasks, as well as a beginner-friendly subset. Issues partially or fully involving web development can also be seen listed here which may involve HTML/CSS/TypeScript/Svelte, although depending on the task, it may also involve Rust (which can be a good way to get gently introduced to the language if you come from a web background).
Writing new documentation by commenting existing code is another valuable way to contribute as you learn from reading code.
Feel free to pick whatever task interests you, then comment on the issue that you would like to start. After commenting, you can dig in right away, then we will assign the issue to you once you have a PR ready. (Always remembering to leave a comment is important, since GitHub doesn't allow assigning issues to people who haven't commented on them.)