PG Doc comments form <noreply@postgresql.org> writes:
> I'm a newbie and may be asking stupid questions... but
> shouldn't it be mentioned in the official documentation on this page
> https://www.postgresql.org/docs/12/postgres-user.html
> that postgresql upon installation automatically creates a system-user that's
> called 'postgres' ?
No, because Postgres as distributed by us does no such thing.
Many vendors' packagings of Postgres create such a user (as is also
often true of their packagings of other service-type software). But
it's up to the package's documentation to tell you about that. Look
for a README-type file installed by the package.
regards, tom lane