Hi, you could visit owasp.org for informations (lot of docs). Securityheader is a matter for the webserver, for example http connection without « s » isn’t allowed . Of course it’s possible to add html code in our site html header but we have to know the configuration of the webserver. I think it’s OUR problem when WE manage our own server. Maybe I’m wrong… I’m agree with @Kunstmaler it’s not an easy task.