It's great to have you posted in the Community forum, @kip-irelandinves. I'll share some insights about this mobile check deposit feature in QuickBooks Online (QBO).
Please know that this feature is still available for those QuickBooks users who sign up for QuickBooks Payments/Checking. If you do, then you should be able to use this feature. It's also a good thing that you're using an iPhone 12 since it's only available for iOS devices. After signing in to your QBO app, here's how to use it:
Go to the Cash Flow menu.
From QuickBooks Checking balance, select Send Money.