Hi Stephanie,
Just add this piece of code before the "Total (HKD)" and "Total (USD)"
'<b>'&"Total (HKD)"&'</b>'
'<b>'&"Total (USD)"&'</b>'
Then, right-click the formula field > Format field > Paragraph tab > Look for the option "Text Interpretation' > Set that to 'HTML Text'.
-Abhilash