Unfortunately, there is no automatic way to track bank time in QBD or QBO.  It needs to be entered at the timesheet level or in the employee's payroll profile each pay period.  I find it easier to deal with a the timesheet level.

I'm hopping on to an older thread here, but i have been trying to figure out how to show our employees how much banked time they have accrued. i only recently switched to QBO but when i was using Desktop, i would edit the internal pay stub email to indicate how much each employee had accrued. with QBO of course I'm not issuing pay stubs (i believe they view them via Workforce, whatever that is). you mentioned updating their individual payroll profiles... i can't see where or how to add accruing banked pay (for the record, we track their hours as 1.5x regular hours)