Show date posted/updated

By default, node types have the option to display or hide submission info.

The node template has an area to display it.

You can see how the format is hardcoded in the template.

<article{{ attributes }}>

  {{ title_prefix }}
  {% if label and not page %}
    <h2{{ title_attributes }}>
      <a href="{{ url }}" rel="bookmark">{{ label }}</a>
    </h2>
  {% endif %}
  {{ title_suffix }}

  {% if display_submitted %}
    <footer>
      {{ author_picture }}
      <div{{ author_attributes }}>
        {% trans %}Submitted by {{ author_name }} on {{ date }}{% endtrans %}
        {{ metadata }}
      </div>
    </footer>
  {% endif %}

  <div{{ content_attributes }}>
    {{ content }}
  </div>

</article>

The Last Updated module provides a block that displays info.

But to add it everywhere, each node has to enable it.

Creating something similar in Views with a rewrite is doable, but tricky.

Views blocks have duplicate contextual links.

These areas in the template could be a layout with meta and content regions.

TODO: Check out https://www.drupal.org/project/updated