orapwd file=password_file_name_with_complete path password=the_password entries = n
n specifies the maximum number of distinct DBAs and OPERs that can be stored in the password file.
Oracle's password file:
If the DBA wants to start up an Oracle instance, there must be a way for Oracle to authenticate this DBA if (s)he is allowed to do so. Obviously, his password can not be stored in the database, because Oracle can not access the database if the instance has not been started up. Therefore, the authentication of the DBA must happen outside of the database. There are two distinct mechanisms to authenticate the DBA: using the password file or through the operating system. The init parameter remote_login_passwordfile specifies if a password file is used to authenticate the DBA or not. If it set either to shared or exclusive a password file will be used.
Deleting a password file:
If password file authentication is no longer needed, the password file can be deleted and the init parameter remote_login_passwordfile set to none.
Password file state:
If a password file is shared or exclusive is also stored in the password file. After its creation, the state is shared. Setting remote_login_passwordfile and starting the database can change the state. That is, the database overwrites the state in the password file when it is started up. A password file whose state is shared can only contain SYS.
Creating a password file:
Password files are created with the orapwd tool.
Adding Users to the password file:
Users are added to the password file when they're granted the SYSDBA or SYSOPER privilege.
USER is "SYS"
select * from v$pwfile_users;