The `<h2>` tag is an HTML element used to define the second level of headings in a webpage. It helps organize content by creating a hierarchy, making it easier for readers to navigate and understand the structure of the information presented. Headings are important for both user experience and search engine optimization (SEO). In a typical HTML document, the `<h2>` tag follows the `<h1>` tag, which represents the main title. Using multiple `<h2>` tags allows for the division of content into sections, each with its own subheading. This practice enhances readability and helps search engines like Google index the content more effectively.