My home page on the app has lost the invoice section ... just has the estimates

Let's perform some troubleshooting steps to fix the issue, Sales

We can refresh the data so the invoice section shows up. To do so, follow the steps below:

For iOS

1. Go to Settings, then tap General.
2. Tap iPhone Storage, then tap the QuickBooks Online app.
3. Tap Offload App.
   
   

This will free up the storage without deleting your app's documents and data.

For Android

1. Go to Menu ☰, then tap More Options ⋮.
2. Tap Settings, then Refresh Data.
3. Tap YES to confirm.

Once done, restart your device and reopen your QBO mobile app to double-check. however, if you're still unable to access the invoice page, you can uninstall and reinstall the app. You can also check out this article for other troubleshooting steps. I've got this for you:  Fix Common Errors In The QuickBooks Online Mobile App For Android.

Moreover. you may want to check out this article so you'll know how QuickBooks records invoice payments. Check this out: Record Invoice Payments In QuickBooks Online.

Let me know if you have any other concerns with your invoices or when using the QuickBooks applications. We're here to help you as always.