any default columns for tracking / auditing purpose

In Postgres 12 and up, are there any default columns available which could
be useful for tracking / auditing purposes ?
e.g.
- real user who entered / updated the data
- timestamp when data was updated / entered
where can i get a list of such default columns (if any) - which could be
accessed easily in user applications.

also what is the usual practice in creating userID's in a large
multi-tenanted applications with highly dynamically changing users (e.g
students who enroll and go off after some sometime), with all users having
the same access -
is a different userID created in the system for each user or is a common
postgresID used by the application and the application is responsible for
tracking individual users with its own userID. (this will reduce system
overhead)

with warm regards
Sanjay