Hello and good day, cchow.

Aside from updating the employee's Social Security Number in QuickBooks Online, you can print their W-2 form.

Here are the steps:

1. Go to Taxes > Payroll Tax.
2. Under Forms, select Annual Forms.
3. Scroll down at the bottom and click the W-2 Copies B, C & 2 link.
4. Select the period, and click the View button.
5. Click the Print icon to print the form. 

If you have already filed the W-2 form with an incorrect SSN, then you must file an amended W-2 form (W-2C) with the IRS. For more information, please check out this article: Correct or amend W-2 forms.

I'll be around if there's anything else you need. Stay safe.

Thank you for a clear, definitive answer!