checkout page details need to have state/province for some country

Hi,
I use theme fuse and i am hosted at siteground.

I use a payment gateway (2checkout) that require mandatory state/province for some country for the checkout page in billing and shipping details.
Some country are missing the state option and some country don’t have a * do make it a mandatory filling.

I would like to give a NA value for all the country so that the payment gateway can get the missing details and approve the payment.

Or is it possible to add the state option for the missing country:FRANCE/NETHERLANDS/ POLAND/ SINGAPORE

country that need to be made mandatory but have a state option :ROUMANIA/SITZERLAND/U.K

The help would be very appreciated.

Thank you