Why does Intuit QuickBooks keep crashing on my iPhone when I convert Estimate to invoice. Upon restart, there invoice is somehow created but the estimated status is same

Thank you for reaching out to the Community, @via-aqua. I want to ensure that this matter is addressed right away.

For most general issues in QuickBooks Online (QBO), clearing the app's cache can help resolve them. By clearing its cache, you can remove the historical data and access QuickBooks with a clean slate.

To start with, let's refresh your data to see the latest available information in your QuickBooks Online app to resolve this unexpected behavior. 

Here's how you can refresh your data on iOS:

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

This will free up the storage without deleting your app's documents and data. If the problem persists, you can uninstall and reinstall the Online mobile application.

Nevertheless, I can guide you through updating the status of the estimate that has been affected.

Here's how:

1. Open the estimate.
2. Click the drop-down list under the name of the customer.
3. Change the status of the transaction in the Estimate status field. 
4. Click Save.

You can also compare mobile app features and see QuickBooks Online access for mobile devices. Please note that these articles are specific to the US region, but they will also work for the Global Platform.

To ensure the issue is resolved for you, please let me know how you get on after attempting the steps. Kindly respond to this post, and I will get in touch with you.