Add tracking numbers to fulfilled orders
If you receive a tracking number after fulfilling an order, then you can add the number to the fulfillment. The number is included in the optional shipping update email that can be sent to the customer.
From your Shopify admin, go to Orders.
Click the order number for the order you want to add a tracking number to.
In the Fulfilled section, click Add tracking:
In the Edit tracking dialog, enter your shipment's Tracking number.
Shopify might recognize the tracking number format and choose a shipping carrier for you. If it doesn't, or if it chooses incorrectly, then choose your shipping carrier from the Carrier drop-down menu.
If your carrier isn't fully supported by Shopify, or if you select Other from the Carrier drop-down menu, then you can enter the Tracking URL manually: This tracking number will appear on the order status page. Make sure that you enter the complete URL (including the digits) that your carrier provided to track the shipment.
Optional: If you don't want a shipping update email to be sent to your customer, then uncheck Send notification email to customer.