Using values in other e-mails / other plugins

Hello,

I am looking for a way to use values/variables generated via the “custom PHP code” in other plugins.

Specifically, I would like to send a shipment tracking link and a bar code to the customer via e-mail.

1) For the tracking link, I need to use the value of this field as a URL parameter:

// get ORDER_KEY from order number, order date, 5 digit random number
add_filter('woe_get_order_product_value_order_key', function ($value, $order, $item, $products,$item_meta) {
return $order->{'order_number'} . '_' . substr($order->{'date_created'},0,10) . '_' . rand(10000, 99999);
},10,5);

(How) can I use this as a variable in an e-mail template? Is there a value in the database I could somehow query? Is it possible at all?

2) With the bar code, it’s kind of a similar problem; I want to convert the item_id into a Code128. There are many scripts/plugins for generating bar codes, but how do I access the item_id values?

Many thanks in advance,
kind regards

Felix