Postgres default password - ubuntu installation


I trying to backup database postgres, when i want to copy backup to my private folder it ask my for password , i have set everyting by default like here below , so password should be chirpstack ??

– create role for authentication
create role chirpstack with login password ‘chirpstack’;

– create database
create database chirpstack with owner chirpstack;

– change to chirpstack database
\c chirpstack

– create pg_trgm extension
create extension pg_trgm;

– exit psql

Can someone advice what could be wrong please ?