Is it possible to file a 941x amended payroll form using quickbooks online payroll (the payroll service)?

Hello there, lindzrogers.

For now, the filing of the amended 941x form is unavailable in QuickBooks Online. You'll have to file it manually.

However, you can print some payroll reports and use them as your reference when filing the corrected 941. I'll show you how:

1. Go to the Reports menu and search for a payroll report. 
2. Filter the dates according to your preferences.
3. Choose Run Report.
4. Click the drop-down arrow from the upper right corner of your screen.
5. Choose Export to Excel.
6. Open the downloaded file and print it from there.

Once done, you can file it outside QuickBooks manually.

Check out the list of available payroll reports you can use as a reference: Run payroll reports.

Keep me posted if you have any additional concerns regarding managing taxes in QBO. I'll be more than happy to assist you. Stay safe.