Display barcode of each product on the invoice or delivery note, woocommerce

I need to display the barcode of the product on the invoice or delivery note, I try to do it with this code but it does not show the barcode image:

<?php
    echo get_post_meta( $product_id, '_ywbc_barcode_image', true );
    ?>

I am using the YITH WooCommerce Barcodes and QR Codes plugin, which adds a barcode for each product, in the following image you can see the meta data that the plugin adds (Product Post Meta).

Answer

You can add a do_action wherever you like the order barcode to appear, assuming you have access to either the $order object or order id, like this:

do_action ( 'yith_wc_barcodes_and_qr_filter', $order->get_id() );

You can then use that to call an action that will display the barcode on all locations you’ve added the do_action:

if ( ! function_exists( 'yith_wc_barcodes_and_qr_filter_call_back' ) ) {
    add_action( 'yith_wc_barcodes_and_qr_filter', 'yith_wc_barcodes_and_qr_filter_call_back', 10, 1 );
    function yith_wc_barcodes_and_qr_filter_call_back( $id ) {
        ob_start();
        $css = ob_get_clean();
        YITH_YWBC()->show_barcode( $id, true, $css );
    }
}

This last part goes in the functions.php of your (child)theme or should be added with a plugin like Code Snippets.

If you need the product barcode you will have to use the product ID instead of the order ID, assuming you have access to the $product object.

do_action ( 'yith_wc_barcodes_and_qr_filter', $product->get_id() );