Best practices :
Contrary to what you may think, the favicon can be of any size and of any image type. Follow this link for details.
Not putting a link to your favicon can slow down the page load.
In a django project, suppose the path to your favicon is :
myapp/static/icons/favicon.png
in your django templates (preferably in the base template), add this line to head of the page :
<link rel="shortcut icon" href="{% static 'icons/favicon.png' %}">
Note :
We suppose, the static settings are well configured in settings.py.