DFF Process

1)define the field in the Canvas
change the field property database items as "no"

2)Define the Package like follows.

Package Specification:
----------------------
PACKAGE DFF_PKG IS
PROCEDURE DFF_PROC(EVENT VARCHAR2);
END;
Package Body:
-------------
PACKAGE BODY DFF_PKG IS
PROCEDURE DFF_PROC(EVENT VARCHAR2) AS
BEGIN
IF (EVENT = 'WHEN-NEW-FORM-INSTANCE' ) THEN

FND_DESCR_FLEX.DEFINE( BLOCK => 'WIP_ITEMS10',
FIELD => 'DFF_TEXT',
APPL_SHORT_NAME => 'WIP',
DESC_FLEX_NAME => 'WIPDFF');

END IF;
END DFF_PROC;

END;

3)Call this Package from WHEN-NEW-FORM-INSTANCE Trigger
packagename.Procedure name('WHEN-NEW-FORM-INSTANCE');
DFF_PKG.DFF_PROC('WHEN-NEW-FORM-INSTANCE');

4)Call another API from WHEN-NEW-ITEM-ISNATCE Trigger
fnd_flex.event('WHEN-NEW-ITEM-INSTANCE');
-It will Populate the DFF in the Form.