I’m happy to see you here in the Community, @usergreencleaningser. I’ll help you make an amendment with your W- 2 in QuickBooks Online.
If you or your employee discover an error after you've submitted your W-2, I suggest creating a W-2c form directly to the Social Security Administration and submitting it manually.
Additionally, go to this article regarding the most common W-2 questions and answers. Also utilize this link to learn what to do in fixing employees' W-2s.
You can always have my back. Just let me know when you need more clarification about W-2s in QuickBooks Online.