It's great to have you reach out to us here. QuickBooks is a versatile program that offers the tools and resources you need in order to move forward with your work. I'll be glad to provide more info and make sure you're on the right track.
Since the T4s in QuickBooks aren't for submission to the CRA, you'll have to manually make the edit outside of QuickBooks. Ideally, when you submit your T4s to the CRA. For reference, here's a helpful article that shows you how to: