KFF vs. DFF: Differences

A flexfield in Oracle Application is a field made up of sub–fields, or segments.  They are basically used to implement code structure or to capture additional information. There are two types of flexfields: key flexfields and descriptive flexfields. A key flexfield appears on your form as a normal text field with an appropriate prompt while a descriptive flexfield appears on your form as a two–character–wide text field with square brackets [ ] as its prompt.
Here is a brief comparison between KFF and DFF: