Security headers are server responses that tell browsers how to treat your pages. They are not a replacement for secure code, but they add useful protection layers.
A good starting set includes X-Content-Type-Options, Referrer-Policy, frame restrictions, and a careful Content-Security-Policy when you understand your scripts and assets.
Content-Security-Policy is powerful but easy to break if copied blindly. Start in report-only mode if your host supports it, then tighten it after watching what the site actually loads.
For static sites, headers are often easier to reason about because there are fewer scripts and external services. Keep the asset list small and the policy can stay simple.
Review headers after adding analytics, embeds, fonts, or third-party widgets because each external dependency may require a policy change.