Appreciate the update, @nlopez8. I'll share details about your app.
With the latest updates, the QuickBooks Online app installed on mobile devices requires the version 11 or higher for iOS and version 7 for android devices to work. Use this article to learn more about the supported versions of iOS devices: What Browser Do you Need for the Best Experience When Using QuickBooks?
However, if you can confirm the latest iOS version is installed on your mobile device, I recommend contacting our Customer Care Support. Then, let one of our specialists inform our engineering team to investigate why the app is crashing. I want to include that reaching out to our team online is best during business hours from 6 AM-6 PM PT Monday-Friday.
I'm adding this article to read and learn more about the features to utilize while using the QBO app: Which QuickBooks Online App Features are Supported on Mobile Devices?
I've got you got you covered if you got questions about invoicing using the app, Let me know by leaving a comment below. Take care always!