I have finally found a solution https://hotexamples.com/examples/-/WC_Order/set_currency/php-wc_order-set_currency-method-examples.html
$order->set_currency('HRK');
I have finally found a solution https://hotexamples.com/examples/-/WC_Order/set_currency/php-wc_order-set_currency-method-examples.html
$order->set_currency('HRK');