Many elements of a web page are repeated on every page in the site, or every page in a section of the site. By writing one parent template for the site, and one for each section, you can easily modify the look and feel of your entire site
The parent template
The parent template defines the elements common to a set of pages, and defines blocks that will be filled by individual pages.
<p>
<a href="{% url 'learning_logs:index' %}">
Learning Log
</a>
</p>
{% block content %}{% endblock content %}The child template
The child template uses the {% extends %} template tag to pull in the structure of the parent template. It then defines the content for any blocks defined in the parent template.
{% extends 'learning_logs/base.html' %}
{% block content %}
<p>
Learning Log helps you keep track
of your learning, for any topic you're
learning about.
</p>
{% endblock content %}