I've been using the app on an android for months, and all of a sudden all my invoices have disappeared and its telling me to create my first invoice

I know a couple of troubleshooting steps to resolve the issue, charljohnson97-g.

Sometimes, the app may produce unusual outcomes due to excessive data. You can fix it by clearing the app's cache.

To clear the cache in your QuickBooks Online app, you can follow the steps below:

• Android - Select the Menu at the bottom and click the Settings icon. Then pick Refresh Data and choose Yes.

To clear cache in your phone settings:

• Android - Select Apps from your phone's Settings (varies by device). Choose the QuickBooks app from the list and pick Storage, then Hit Clear data.

I suggest referring to these articles for more comprehensive troubleshooting details regarding the QB Online app:

•  Fix common errors in the QuickBooks Online mobile app for Android. 
• Clear cache and cookies to fix issues when using QBO.

I'll keep this thread open if you have additional details about this problem. I'm here to assist you more.