To change the password for the ADMIN account:
1) Change your working directory to the apex directory where you unzipped the installation software.
2) Start SQL*Plus and connect to the database where Oracle Application Express is installed as SYS specifying the SYSDBA role. For example:
On Windows:
SYSTEM_DRIVE:\ sqlplus /nolog
SQL> CONNECT SYS as SYSDBA
Enter password: SYS_password
On UNIX and Linux:
$ sqlplus /nolog
SQL> CONNECT SYS as SYSDBA
Enter password: SYS_password
3) Run apxchpwd.sql. For example:
@apxchpwd
4) When prompted enter a password for the ADMIN account.