@prakashpunj
By default it uses sqllite as Database (no password). However, you can try checking the following files for more details on the Superset host.
# grep 'SUPERSET_DATABASE_PASSWORD' /etc/superset/conf/superset_config.py
# grep 'SUPERSET_DATABASE_PASSWORD' /var/lib/ambari-agent/data/command-*
.
Via ambari Ui you can check
Ambari UI --> Superset --> Configs --> 'SUPERSET META DATA STORAGE CONFIG' (tab)
Search for "Superset Database password" section in the above page and verify if it is empty or password is set.
.