Some files have deleted after download iPadOS 18.1

Try restarting your iPad - as this will often clear an isolated or post-update software issue:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. When the Apple logo appears, release the top button.

Force restart iPad (models with the Home button)

Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.

If the problem persists after performing the restart, your missing files have been lost.

Do you have an iCloud or iTunes backup of your iPad - created prior to updating your iPad? If so, all locally stored data van be restored to your iPad:

Restore all content to iPad from a backup - Apple Support

What type of files are affected - and where were the files stored?

The Files App will show files that are stored locally on your iPad, in iCloud storage, other Cloud storage services - and USB storage devices if connected to your iPad.

If you value your data, always keep a backup. Unfortunately, you may have irretrievably lost your files.

I'm a published writer, ALL my files are gone after that 18.1.1. ????