When trying to send invoice the app just shuts down and goes to phone Home Screen.

Let's work together to ensure you can send invoices using your QuickBooks Online (QBO) app, Stuart.

When the app's storage data is almost at its limit, it causes odd behavior where you are unable to send invoices. To resolve this, we can delete the cache from your application to use it again with a clean slate and all of its capabilities at your convenience. Here's how:

For Android

1. From your QBO app, select the Menu icon.
2. Next, choose Settings. 
3. Then, select Refresh Data and click Yes.

For iOS

1. Click the Menu option located at the top right.
2. Then, choose Help & Feedback.
3. From there, click Refresh Data and select Refresh.

You can also do this on your phone settings. I'll guide you on how:

Android device

1. Tap your phone's settings and select Apps.
2. From there, look and choose the QuickBooks app.
3. Next, Storage and click Clear data.

iOS device

1. Go to your phone's settings, and click Settings.
2. Next, select General and choose iPhone Storage.
3. Look for the QuickBooks app and select Offload App. This will only free up the storage without deleting the documents and data of the app.

Once done, attempt to send the invoice again. If the same happens, we can uninstall and reinstall the application to start fresh. Follow the steps below to delete it:

1. Tap and hold QuickBooks Online on your phone.
2. Drag the app to the Uninstall section.
3. Press Yes to confirm. 

Additionally, here's a helpful source that can provide you with more information on how the QBO app works as well as those features available:

• Compare mobile app features
• QuickBooks Online app overview

We've always got your back should you need assistance when doing tasks in the QuickBooks app such as managing your invoices or any QuickBooks-related concerns. Drop your reply anytime and we'll get back to you. Take care always, Stuart.

It’s a bug on the IOS app.

Instead of clicking the SEND button (which just causes the app to appear to quit), go into the invoice, tap the 3 dots top right and select email. You can then send as normal.

Quickbooks are aware of the bug and it’s in their list to be fixed.

You may also see a popup (also a bug which Quickbooks are aware of) saying:

Invoice needs approval

The changes made to invoice needs an internal approval before it can be sent to the customer

You can ignore this message as the invoice is sent.

See my other post here…

https://quickbooks.intuit.com/learn-support/en-uk/other-questions/my-employees-are-getting-a-message-pop-up-when-trying-to-send/00/1553797