Welcome to the QuickBooks family, sandrabrown.
Yes, you can purchase QuickBooks Payroll standalone in QuickBooks Online. We have three (3) payroll plan that you can select. These are:
Each plan has a different cost but more importantly, with more features. To know more about this, you can check this link: https://quickbooks.intuit.com/payroll/pricing/.
If you're unsure about committing to a new version of QuickBooks, you can test out the products for 30 days. Just toggle the radio button to Free trial for 30 days and hit Try it free.
If there's anything else I can do for you, let me know by commenting below. I'd be happy to further assist you. Have a great day.