Hello, @Katherine Rowe.
I’d like to answer your question about accessing prior payroll.
You can get a copy of your 2017 W-2s under the View Archived Forms section in QuickBooks if you used our service during that year. Since you subscribed on 01/01/2018, I advise contacting your previous payroll provider to get a copy of the form.
Once you got the payroll information, you will need to create a fill-in version of Form W-2 for SSA. Check out this link for more information: https://www.irs.gov/forms-instructions.
That should do it. If you need anything else, don’t hesitate to let me know. I’m always here to help. Have a good one!