Square Payroll is priced separately from Square's payment processing, typically a flat monthly base fee plus an additional charge per employee or contractor paid that period. A contractor-only plan exists at a lower cost for businesses that only need to pay 1099 workers and don't run a W-2 payroll at all.
If a business already uses Square's Team Management for scheduling and timecards, hours clocked at the register flow directly into Square Payroll without anyone re-entering them, Square's own version of connecting sales-floor activity to a pay run.
Square Payroll calculates and files federal and state payroll taxes on the business's behalf and supports direct deposit to employees, which covers most of the compliance side a small business would otherwise have to handle separately.