After some workaround, I will get to know the headers with submenus can able to create using “Header submenus” component in discourse. But it is added before the discourse header.
Actually, I want to integrate my own headers with submenus inside the default discourse headers using any default theme settings or component or custom html, css and javascript.
The dropdown looks like,
Above dropdown should integrate with below mentioned discourse headers,
And also, it shouldn’t affect the behavior of existing logics or alignment of discourse.