Resolving the issue when after billed the tracking number will be not displayed

Create a sales order and fulfill that order. Then it redirects to the item fulfillment page there is a sub-tab package.

Fill the below fields :

1) LBS

2) Package contents description 

3) Package tracking number 

4) Save

Ex: LBS: 8, Package contents description: FedEx, Package tracking number: 450745776791  

And do the billing then,

In the website login and in my account track items column. The tracking number will be displayed