As mentioned in Payroll - Shift Approvals shifts need to be generally approved and then approved for payroll.
To approve all shifts for payroll for an Employee you can simply select "Approve all shifts for payroll".
To approve individual shifts for payroll, you can click on the grey section highlighted upon hover of your mouse or click the Actions button and "Show Detailed View"
In the Detailed View, you can approve individual shifts for payroll.
As you can see above, if a comment was left as part of the general shift approvals, you can see it here also, so you have context, on why a shift has been approved that may be outside the expected time and attendance records.
Approved for Payroll
This icon the shows that the Shift has been Approved for Payroll.
Number of Shifts that still require Approval
And then above we can see that we still have a further 3 shifts to Approve for payroll.
Unapprove Shift for Payroll
If you need to unapprove a shift for payroll for any reason. You can do so by clicking the Actions and then Unapprove for Payroll.