How to show empty fields inside of email Notification?

I need the "For Office Use Only" hidden fields section to show up in the email submissions received 

If I understood you correctly you want that fields from section "For Office Use Only" are shown inside of email notification when your users submit you form. I have inspected your form and those fields are set to be Read Only, which means that your users will not be able to fill them and because Hide Empty Fields option is set to Yes inside of your email Notification settings, mentioned fields will not be shown.

If you want that mentioned fields, which will be empty, are shown when your users submit your form then you need to set Hide Empty Fields option to NO.

Hope this will help. Let us know if you need further assistance.