These fields can be controlled from the Self Registration Setup window.From Admin mode choose Options> Self Registration Setup.
The Self Registration Setup window when first opened showing all the fields available to VisitorRego:
Database FieldThe name of the database field. It doesn't matter what the Registration Screen name is - the on screen field maps to this database field. This field can't be changed.Field LabelThe label of the field as it appears on the Registration screen. This label can be renamed as required.VisibleWhether the field is visible on the Registration Screen or not. When checked the field will appear on the specified tab.WidthIf the field is visible it will be drawn to the specified width (the unit of measure is a screen pixel). It will be on the specified tab, in the specified tab order.LinesIf the field is visible it will be drawn to accommodate the number of lines specified. It will be the specified width, on the specified tab, in the specified tab order.TipsWhen the field is clicked in, the tip appears in the status bar on the bottom of the Registration Screen.Fields that appear on the Registration Screen are site specific. Registration fields need to specified for each site (other than using the default setup).