Header tags are HTML elements (H1, H2, H3, H4, H5, H6) that organize your content into a hierarchical outline, much like chapters and sections in a book. The H1 is your main title, H2s are major sections, H3s are subsections under H2s, and so on. Search engines parse this structure to grasp what your page covers and which topics you prioritize. Users scan headers to decide if your content answers their question, so clear, descriptive headers reduce bounce rate and improve dwell time—both indirect ranking factors. From an SEO standpoint, your H1 should contain your primary keyword naturally and describe the page's core topic. You get one H1 per page in most cases. H2 tags break the content into major talking points; weave in secondary keywords here without forcing it. H3–H6 tags add depth when a section needs further breakdown, but most pages rarely need anything past H4. Google's algorithm doesn't weigh H5 or H6 heavily, so keep your hierarchy shallow and logical. Common mistakes we fix at Ottawa SEO: multiple H1s (confuses topic focus), skipping heading levels (jumping H2 to H4), and keyword-stuffed headers that read like spam. A clean structure might be H1 for the title, three to five H2s for main sections, and H3s only where you genuinely subdivide a section. Tools like Screaming Frog or the browser's Inspect Element let you audit your header stack in seconds. Header tags also matter for accessibility—screen readers rely on them to navigate content—so semantic HTML benefits both users and bots. For local businesses in Ottawa or Toronto, including geo-modifiers in an H2 (not the H1) can reinforce local relevance without over-optimizing. In practice, headers are a lightweight win: they cost nothing to implement correctly and can lift rankings 5–15 percent when paired with strong content and internal linking. Treat them as your content's table of contents, and both Google and readers will follow along easily.