Not sure what you mean by " formating code". The VBA code
"behind" a report is in the report's class module. Just
open the report in design view and use the View - Code menu.
OTOH, each text box on a report has a Format Property where
you could specify the formatting codes for the data in the
text box.
OTOOH, formatting a text box may also be done using an
expression in a text box's ControlSource expression.
But then, maybe you're looking for the stuff that can be
specified by using the Format - Conditional Format menu
item.