title in page.html.twig
This is my solution for adding title to page templates.
in yourthemename.theme add 

function hook_preprocess_page(&amp;$vars) {
    if(isset($vars['node'])) {
        $vars['title'] = $vars['node']-&gt;title-&gt;value;
    }
    else{
       $vars['title'] =$vars['page']['#title'];
    }
 } 


then title exist in page templates.