How to add custom block region on drupal 8

  1. Open file exists in /core/themes/YourThemeName/
    • Add the string "header1 : Header1" under the keyword regions:
      name: YourThemeName
      type: theme
      description: 'YourTheme'
      package: Core
      base theme: classy
      version: '1.0.0'
      core: '8.x'
      project: 'drupal'
      datestamp: 1502903957
        content: Content
        header: Header
        headline: Headline
        primary_menu: 'Primary menu'
        secondary_menu: 'Secondary menu'
        footer: Footer
        highlighted: Highlighted
        sidebar: Sidebar
        header1 : Header1
  2. Open page.html.twing file exists in /core/themes/YourThemeName/templates
    • Place the following region into where you want to place through this file:
      {{ page : header1 }}