I can't seem to locate the app transactions that I've exported (from a payroll website called Justworks). Do I need to sync or update anything on the quickbooks side?

Hi there, ed-franowicz-lea.

I can share some information about importing transactions to QuickBooks Online

If you're unable to locate the app transactions you exported from a payroll website like Justworks in QuickBooks Online, it's important to consider the integration and support between your payroll software/service and QuickBooks Online.

While QuickBooks Online strives to provide seamless integration with various payroll providers, it's important to note that if your payroll software/service isn't fully integrated or supported by QuickBooks, the data import process may vary. This means the transactions exported from Justworks may not automatically appear in QuickBooks Online. That said, I recommend consulting Justworks support to make sure all your payroll transactions are exported successfully. 

Also, you can read this article to learn how to properly enter payroll checks created outside of QuickBooks as journal entries: Manually enter payroll paychecks in QuickBooks Online.

Let me know if you have any other QuickBooks Online or payroll-related concerns. I'll be happy to assist. Have a great day!