If there is no Box D (control number) on your W-2, then it is most likely an indication that your employer either does not have one, or did not issue one this year. This means that you cannot electronically import your W-2 tax document; but will instead need to manually enter the data. Don't stress too much, however, because entering a W-2 typically takes just a few short minutes.
Please allow us to explain this in more detail.
Form W-2 (wage statement) Box D is a Control Number field. It is usually located below or near the Employer's Name and Address.
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, and is needed if attempting to
electronically import your W-2 into a tax software program (like
TurboTax). Please note that not all W-2s (or employers) will
necessarily include a Box D number. Your alternative to importing a W-2
document is to simply input the same information manually.
actual Control Number itself is basically not necessary in completing
your tax return, unless you wish to import your W-2 into TurboTax; and
it that one instance it is required. In other words, the W-2 Control
Number, whatever it is, will never increase or decrease your actual tax
refund (or your amount owed) by a single penny.
To make things clear, you do not need data from Box D at all, in order to accurately file your income tax return. In fact, you can simply leave the field blank in the TurboTax program. The
exceptions to that would be if you are attempting to e-file your return
and see some sort of W-2 Control Number related error; or if the program
insists on a value before allowing you to continue. In those cases, we
have a TurboTax FAQ article that can help. I've linked this answer to
that FAQ page below.
We hope this information is useful to your needs. Thanks for asking this question.