Let's sort this out together, MRT82, so you can resume creating invoices on your mobile app.
The create invoice option should be available on mobile devices. However, if you're having issues with this disappearing, we can perform troubleshooting steps to identify if we can resolve the app's problem.
To get started, we have to ensure the app version is updated. This way, we can determine that it has the latest available information to solve common issues. To do that, we have to:
Go to the Apple Store or Google Play.
Choose QuickBooks.
Then, tap Update.
After performing the steps mentioned, we can also clear the app's data of the application to refresh it and remove errors that might be causing the issues you're having. Perform the following:
For Android:
Select the Menu at the top left corner and choose Settings.
Then select Refresh Data.
To confirm, tap Yes.
For iOS:
Go to Menu and click Help & Feedback.
Select the Refresh Data.
Press Refresh to confirm.
If the issue persists, I recommend uninstalling and reinstalling the mobile app to fix the problem. Here are more links on how you can reinstall your QBO app.