This extension mounts into the SharePoint Online Top placeholder to render a responsive global header with a customizable brand area, desktop mega-menu navigation, and a mobile drawer. It includes built-in tools for search, profile info, bookmarks, notifications, and accessibility controls. You can also enable an optional HTML footer in the Bottom placeholder and inject SEO metadata dynamically from your navigation terms.
Open this sample in the gallery (popup panel): Open in gallery
Source: https://github.com/pnp/sp-dev-fx-extensions/tree/main/samples/react-application-navigation-header