Database or application users? Your question doesn't make a great deal of sense from an application point of view as you don't really have "users per module". And from a database perspective the users (schemas) will have been created when you did the install.
What are you actually trying to get?
Module name and user name are same for oracle application say gl is the password for gl
By default apps and applsys password is apps, sysadmin password is sysadmin
sys and system passwords are defined/given at the time installation