FAQ: What Does the Quickbooks Tab on the Employees Account Do?

FAQs - 
That feature is a simple way of adding your employees basic information into QBO.  Name, Address, Email, Employee ID, Hire Date, and DOB will appear in QBO if you click the connect to Quickbooks button for an employee. 

NOTE -- You cannot push your payroll data from MC directly to QBO.  (You can use Quickbooks to run your payroll if that's the payroll processing company you want to use, but you'd still have to manually enter the numbers generated from MC into the payroll section of QBO.)