How can I display site logo, name and slogan?
function mytheme_preprocess_page(&amp;$variables) {
  $site_config = \Drupal::config('system.site');
  $variables['site_name'] = $site_config-&gt;get('name');
  $variables['site_slogan'] = $site_config-&gt;get('slogan');

  // logo needs to be placed within specified folder
  $variables['logopath'] = file_url_transform_relative(file_create_url(theme_get_setting('logo.url')));

}


Then in page.html.twig you can use variables site_name and site_slogan as follows:

{{ site_name }}
{{ site_slogan }}


and for the logo:

&lt;img src="{{ logopath }}" /&gt;


note: logo image file will need to be available in your current theme's root folder (or subfolder of your choice).