A flexfield is a flexible data field that your organization can customize to your business needs without programming. Descriptive flexfields can be context sensitive, where the information your application stores depends on other values your users enter in other parts of the form. A flexfield is a field made up of sub–fields, or segments. Descriptive Flex Field (DFF) in Oracle Applications. The most powerful feature of Oracle Applications is the Flexfield feature. Step 1: Create the custom table · Step 2: Register the custom table · Step 3: Register the DFF in Oracle Apps · Step 4: Configure Forms Builder · Step 5: Develop the.