Add the 2 digit state abbreviation for United States to the invoice export

Hello, we periodically need to print and mail invoices. We willl be using a 3rd part software app to create the invoices. It would be very helpful if the invoice export file would include the 2 character abbreviation for the State field, rather than the spelled out field. For example: if a field could be added where the state “Wisconsin” had a corresponding state abbreviation field “WI” that would be beneficial. Thanks!