Hi there, @mjacobwa, and Welcome to the Community space.
Allow me to share some insights as to why the checked box 13 on W-2 under Manage is not showing up on pdf in QuickBooks Online.
This might be due to report health insurance or retirement plans on your W-2s QuickBooks Online Payroll. If you need to report employer-sponsored health insurance amounts in Box 12DD or 12FF, or you contributed to a retirement plan that you tracked outside of QuickBooks (Box 13), you can add this info to your W-2s.
Select Taxes, then Payroll Tax.
Select Filings.
Select Resources.
Select W-2s.
From Employee W-2s, select Edit Box 12/13 on W-2 Copies B, C, & 2 (employee).
Enter the amounts or select the checkbox in the Box 13 column for each employee needed.
Select Submit.
For a more detailed step, you can check this article: Preview your W-2s.
Moreover, I'll also share these articles you can read if you want to learn more about W-2s:
Thank you. The steps you outlined are exactly what I did under the Resources tab and it shows there that Box 13 should be checked but when I view the employee W-2 to print it, Box 13 isn’t actually checked.