Header template does not appear on all pages

Hi,

If you want to have a global header you’ll need to set it in theme panel -> https://www.screencast.com/t/dnHozn7zH and all pages/categories/posts that do not have set an individual header will have that header set.
For individual header you’ll need to edit that page/post template/category template… and set in it the header that you want, and on this posts/categories templates or page will be set that header ( the individual will override the global header for that post/page ).

Thank you for your understanding!