To add currency for the Vehicle Rate Add on plugin is very simple. Just use the “wpcvr_currency_country” filter. this filter has one arguments “$currency”.

// In this sample code in adding Central African CFA franc currency.
add_filter('wpcvr_currency_country', function( $currency ){
    $currency['CFA'] = 'Central African CFA franc (CFA)';
    return $currency;
},10, 1);