WooCommerce - Adding Custom Product Meta Fields

<?php

/**
* Display the custom label field
* @since 1.0.0
*/
add_action(
    "woocommerce_product_options_general_product_data",
    "hoog_add_custom_product_fields"
);

function hoog_add_custom_product_fields()
{
    // Add Custom Input
    $args = [
        "id" => "ean",
        "label" => __("EAN", "hd"),
        "class" => "hd-ean-label",
        "desc_tip" => true,
        "description" => __("This will add EAN to the product", "hd"),
        "data_type" => "text",
    ];
    woocommerce_wp_text_input($args);

    // Add Custom Input
    $args = [
        "id" => "gtin,
        "label" => __("GTIN", "hd"),
        "class" => "hd-gtin-label",
        "desc_tip" => true,
        "description" => __("This will add GTIN to the product", "hd"),
        "data_type" => "text",
    ];
    woocommerce_wp_text_input($args);
}

/**
* Save the custom field
* @since 1.0.0
*/
add_action(
    "woocommerce_process_product_meta",
    "hoog_custom_general_fields_save",
    10
);
function hoog_custom_general_fields_save($post_id)
{
    $ean = $_POST["ean"];
    update_post_meta($post_id, "ean", esc_attr($ean));

    $gtin = $_POST["gtin"];
    update_post_meta($post_id, "gtin", esc_attr($gtin));
}