When calculating the shipping fees, usually the City / Post Code / State fields are not necessary; Country is sufficient.
To remove these fields, use the following snippet:
add_filter( 'woocommerce_shipping_calculator_enable_city', '__return_false' ); add_filter( 'woocommerce_shipping_calculator_enable_postcode', '__return_false' ); add_filter( 'woocommerce_shipping_calculator_enable_state', '__return_false' );