Change Currency for Manual Orders in WooCommerce https://wpsites.net/?p=114652

wc-manual-order-currency-change.php

add_action('woocommerce_new_order', 'set_custom_currency_for_manual_orders', 10, 1);
function set_custom_currency_for_manual_orders($order_id) {
    // Check if the order is manual (admin-created) by looking at the order status
    $order = wc_get_order($order_id);
    $order_status = $order->get_status();
 
    // Specify the custom currency code you want to set for manual orders
    $custom_currency_code = 'EUR';
 
    // Check if the order is manual (e.g., status is 'on-hold' for admin-created orders)
    if ($order_status === 'on-hold') {
        // Set the custom currency for the order
        $order->set_currency($custom_currency_code);
        $order->save();
    }
}