FIELD_PROMPT is a 30 character field which is used throughout the application to provide the ability for users to give a field a prompt.
One usage of the field is for distribution segments. When the Distribution Editor button is invoked on various forms (e.g. IDDP, IDPS, IDJB, IEAS, IPTR, IPPH, etc.), the value in this field is used as a side label for the segment to be entered.
Another usage for this field is with user defined fields in IMUF. When a user defined field is created the user must supply a 'prompt' so that the end user understands what the udf is for.