I am able to get Order and all line items using API endpoint. I also need to get package dimension for this order, after it has been delivered to the customer.
How can I get this data? Is there any API endpoint to get delivery/shipment/fulfillment data.
My app is only able to call merchant store. Do I need to make call to carrier on behalf of merchant and get the parcel details?
These properties would not be available natively via Shopify's API. It could be possible that you can get this information from the Carrier Service.