A_DB2_PASSWD should be set to the password assigned to the database account associated with the user name specified by A_DB2_LOGIN. Not all data sources require a password. Those that do may have case requirements. Check your data source documentation to determine if password is case-sensitive.
If the account with the user name in A_DB2_LOGIN has the associated password CW021535, you would specify:
in the Database Connectors.
For better security, you can accept a password from the user during program execution; set the A_DB2_PASSWD variable based on the response:
ACCEPT RESPONSE NO-ECHO. SET ENVIRONMENT "A_DB2_PASSWD" TO RESPONSE.