Form W-2 (wage statement) Box D is a Control Number field. It is usually located below the Employer's Name and Address.
The Box D Control Number is a code that identifies your unique Form W-2 document in your employer's records. This number is assigned by the company's payroll processing software. Please note that not all W-2s (or employers) will include a Box D number.
The actual number itself is completely irrelevant to completing your tax return, unless you wish to import your W-2 into the TurboTax program, and it that one instance it may be required.
However, if you choose to type in your W-2 manually, then you do not have to enter anything from Box D at all, if you do not want to. In fact, you can simply leave the field blank.
I hope this information is useful to your needs. Try this W2 import information page.
https://ttlc.intuit.com/replies/3389204
(Edited: 02.24.2016 | 11:45a PST)
