Where can I find my order number?

Where can I find my order number?

I ordered a new phone.  I went My TMobile\Other Links\Order Status. The screen is asking for my Order Number and Zip Code.  I do not have my Order Number.

I don't understand why I even have to enter the information.  My T-Mobile should already have that information, and should just show me the status, invoice, and details.

Thanks,

Jake

Order Status