I'm here to help you, usergavincooper50.

This behavior when invoices are not showing as sent can be fixed by clearing the app's data. This helps refresh the application and eliminates common issues that cause your screen to freeze. Clearing the app's data can be done on the app or on your phone settings. You can follow the steps below:

• For QuickBooks Online app:
  • iOS - Select the menu at the top right and then choose Help & Feedback. Then select Refresh Data and Refresh.
    
• In your Phone Settings:
  • iOS - From your phone's settings, select Settings, then, click on General and choose iPhone Storage. Select an app that's taking up a lot of space. To free up the storage without deleting the documents and data for the app, select Offload App.

You can refer to this article for additional troubleshooting options to fix issues with mobile apps: 

You might be interested in learning more about accepting mobile invoices in QBO: How to accept mobile invoices: A guide for small businesses.

Feel free to visit this article to find answers to your other QBO mobile questions: QuickBooks Online Mobile app FAQ.

I'm looking forward to hearing from you. Get back to me if any additional questions about managing invoices that may arise. Have a good one.