Scanned documents are disappearing from Notes.

Hello mhelke,

Thank you for posting in Apple Support communities. We understand that you are having trouble with scanned documents in notes disappearing. We would love to help you with this. 

This document tells you how to use notes: Use Notes on your iPhone, iPad, and iPod touch

This documents tells you how to locate deleted or missing notes: If you're missing notes on your iPhone, iPad, or iPod touch

This document tells you how to scan documents using your iPad: How to scan documents on your iPhone, iPad, or iPod touch

Since you're using an iPad if you have a Mac scanning continuity might be available, if so you can use this article to tell you how to use scanning continuity: Use Continuity Camera on your Mac

Thank you for allowing us to support you.

Have an awesome and productive day!