passwords for checkstubs

RE: He has already tried the 3 letters followed by the last 4 digits of his SS#.

Yes, that's what it should be, per QuickBooks:

How to retrive my checkstubs for personally reason

You can retrieve your check stubs by reprinting them using the voucher check style, Rturrentine. Let me walk you through the step-by-step process below.

When printing, use the voucher checks since it has one check per page and includes the check stubs. Here's how to reprint:
 

1. Go to Lists and select Chart of Accounts.
2. Double-click the bank account you used for the check.
3. Find the check you want to reprint, then double-click it.
4. Click Print, then enter the check number and select OK.
5. Choose your printer settings.
6. Under the check style, tick Voucher.
7. Hit Print.
   

Additionally, if you want to see a more detailed insight into your business's finances, visit this article: Run payroll reports.

With these steps, you can successfully retrieve and print your check stubs. If you need more assistance with handling checks or any other concerns, please leave a comment below. I'm always here to help you.

@NicoleAscencionS   The question is about check STUBS, not checks.  

@Rturrentine   If you are an employee and you want to view the pay stub, your employer will send you an email invitation to access the pay stub through workforce. If you're an employer, you can check it in the Paycheck list.