I have a spreadsheet (from QB) that I need to upload. It is payroll data from the period in advance of starting with QBO. Would like verification on uploading.

You may utilize an importer tool to import your historical payroll data as journal entry

https:// transactionpro.grsm.io/qbo

I'd like to provide additional information, elhsaa-emmerling.

Aside from the importer tool shared by Fiat Lux - ASIA, you'll want to manually enter prior payroll in QuickBooks Online while the option to import it directly within the system is unavable. 

Start with gathering your employee's W-4s, pay stubs, or other payroll reports to help you enter employee's details. Then, continue the process by following the second step on this reference: Set up a prior payroll for QuickBooks Online Payroll.

Also, make sure to run your payroll reports from time to time to keep track of the transactions that you've created so far. 

Let me know if you have other questions. Take care and have a great day!

Sorry but this did not help me.  I need to get this information into QBO or the W-2's will be incorrect.