I started yesterday developping my first app. Im looking 2 things :
Thank you 🙂
What is the tracking code's purpose? Is it for a shipment/order, product, or site analytics?
If it's for a shipment, you would use the fulfillment APIs (creating a fulfillment, or creating a Fulfillment Service) and specify the tracking code. Shopify would handle displaying the tracking code in the order details pages for admin and customer.
If it's something related to a product rather than specific orders/users, you could use a metafield to store it.
I'm still not sure what kind of tracking purpose. Can you describe it more please?
Can you please also describe what you mean by tracking orders?