What is purpose of field codes?

[Tony]

What is purpose of the template fields in the Word Invoice template? They
seem to be superflous inasmuch as there is no data entry wizard, and data is
only entered by deleting the field code?

 

[Suzanne S. Barnhill]

Without looking at the template I would guess that the field codes are
either form fields (in which case the document should be protected for forms
to work correctly) or they are calculated fields, in which case they require
data to be entered in the relevant table cells. The calculation fields would
then need to be updated.