HTML (HyperText Markup Language) is the standard markup language for web pages. Browsers use it to render structure and content: headings, paragraphs, links, images, forms, and more. HTML describes what content is, not how it looks—that is the job of CSS.

Every HTML document has a basic structure: a doctype declaration, an html root element, head (metadata, title, links to stylesheets), and body (the visible content).

HTML is made of elements. Each element is wrapped in tags: opening <tag> and closing </tag>. Some elements are self-closing (e.g. img, br). Attributes go on the opening tag (e.g. href on a, src on img) and provide extra information.

Common elements: headings (h1–h6), p for paragraphs, a for links, ul/ol and li for lists, div and span for grouping (div is block, span is inline). Use semantic elements when possible: header, main, nav, article, section, footer so screen readers and search engines understand the page.

Semantic HTML means choosing elements that match the meaning of your content. A button that submits a form should be <button type="submit">, not a div with a click handler. A list of navigation links benefits from <nav> and <ul>/<li>.

Good semantics improve accessibility (screen readers, keyboard navigation) and SEO. They also make the DOM easier to style and maintain.