The H1 header tag is the most important header for indicating the primary topic and keyword of a page.

The H1 header tag is indeed the most important header. It serves as the primary title for the page content, signaling to both users and search engines what the page is fundamentally about. Search engine algorithms use the H1 to understand the page's main topic and keyword focus, which is crucial for ranking relevance. While other headers (H2, H3, etc.) organize content and provide structure, the H1 holds unique significance in defining the page's core subject.