Server version:

pg_config --version

Client version:

psql --version

Config files in /var/lib/pgsql/data/

Authentication:

• trust: everyone can access everything.
• password, md5, scram-sha-256: password-based.
• ident: makes use of the maps defined in pg_ident.conf. When this is specified for a local (non-TCP/IP) connection, peer will be used instead.
• peer: obtains user name from operating system and checks if it matches database user name. Only supported on local connections.

Check where the data area is:

ps aux | grep postgres | grep -- -D