For example if you select a ban account from a list of 3 choices, add the ANB for that account in a hidden saved field so that it can be used in the tax invoice receipt.
The element would be:
If <field A> = (not =, contains ect) <ABC> then set Field B to <This Value> and have ability to show or hide the field.
for example Gender = Male Set Gender data input field to M
If birthday is between this day and that day set year level field to