Django - How to make views for the entire site?

Question

Django

Might be a stupid question, but. )
There is an application "Private messages" in which the user's new personal messages are counted.
For example, roughly speaking
views.py
def massages():
...
# New messages (number)
new_m = massages.count()
...
How to make these new messages appear (work) throughout the site (project), and not only in this application?
Do I need to write something in settings?

Answer 1

https://toster.ru/answer?answer_id=1074088#answers...