You can either skip that section and leave it blank. Or if you are receiving an error, just put in any combination of numbers in this specific format 5 digits, space, 5 digits (for example, 12345 67890).
That is just a number that the payroll team uses to identify your W-2
for their system purposes.This is not something the IRS needs, so as
long as you input something in this format, you can proceed.
A Control Number (Box D) is used by many payroll departments to uniquely identify a W-2 in their system. If your W-2 doesn't have one, it's no big deal – you can simply leave it blank.
If you get errors when attempting to e-file with an empty Box D, just enter any number in this format: 5 digits, space, 5 digits (for example, 12345 67890). The IRS doesn't care what's in Box D because its use by payroll departments is optional.
On the other hand, if you're trying to import your W-2 with a blank Box D, click skip import and then manually enter your W-2. You won't be able to import using the 5 digit + space + 5 digit solution for e-filing.
If upon going through these steps it is still not letting you e-file, then yes, I would go ahead and print off the return information and mail in into the IRS.