If you haven't run your first payroll in QuickBooks Online, then yes, you can add the payroll information through prior payrolls.
Here are the steps:
On the left panel, click Payroll.
From the Employees tab, click the employee'sname.
In the employee's profile, click the Enter [Year] prior pay details button. Note: Make sure to enter the employee's pay schedule and pay rate so you can see this option.
Follow the on-screen instructions and enter the payroll history.
I’m setting up online qb payroll. I’ve paid myself ( I’m only employee) 7xs so far this yr 2021. How do I go back and add these pay periods or dates I paid myself? I usually pay every other wk so 24 yoga lay periods for the yr...