Filters whether or not to use the international address form. By default, this is set to true to allow any form of address.  When set to false, this will display the shortened “US” version.

apply_filters("pmpro_longform_address", true);

Parameters

bool (true)

Source

File: https://github.com/strangerstudios/paid-memberships-pro/blob/master/pages/billing.php

File: https://github.com/strangerstudios/paid-memberships-pro/blob/master/pages/checkout.php