Help text (or guidance text) is important. It helps the form creator clarify their intent to the form filler.
Most fields support help text. To add help text:In case you can't find the 'Help Text' option after checking 'Show more configuration options.', it means that the chosen field type does not (currently) support help text.
Hint text (or placeholder text) provides a quick prompt to the form submitter, until they start typing.
As soon as the form filler starts typing, hint text disappears. (Whereas help text never disappears.)
Most fields support hint text. To add hint text:
In case you can't find the 'Hint Text' option after checking 'Show more configuration options.', it means that the chosen field type does not (currently) support hint text.