Have no back arrow after invoice creation on my iPad thru the app. This Is only a new issue. How do I fix ?

Howdy, afasnewcastle. 

When the application is not fully functional, performing the recommended basic troubleshooting steps will resolve the issue. To get this sorted out, as an initial step, let's clear the application's cache files. Doing so helps in fixing any sorts of errors in the system. 

Here's how:

1. Go to Settings and click Setting General iPhone Storage.
2. Choose an app that's taking up a lot of space.
3. To free up the storage without deleting the documents and data for the app, hit the Offload App.
    

Once refreshed, restart your mobile phone, go back to your invoicing and check if there's back arrow. If you get the same result, uninstall and reinstall the QuickBooks Online mobile app. 

Additionally, you can visit this write-up: Compare mobile app features. It provides you more information on what options you can access on the customers' and vendors' side as well as a chart to easily compare feature availability on supported devices. 

If you have any other follow-up questions about your invoices, let me know by adding a comment below. I'm more than happy to help. Have a good one!