PDF file corrupted and became a blank file in iCloud

GREGLB wrote:

Hello

Recently I was working on my iPad and editing (adding notes) on a pdf file that I had downloaded from a website. After 6 weeks, while I was adding notes to it, it almost completely became blank and the file size became really small compared to what it was a couple of minutes before. Whenever I try to access it, it just says file corrupted... (bold mine)

If the file size dropped like that, I'm afraid the notes are likely gone. Maybe try copying the file to other places in the future.

It doesn't seem like the file was deleted, but I suppose you could try - Recover deleted files on iCloud.com - Apple Support

If it's critically important, you could restore your most recent backup - Restore your iPad from a backup - Apple Support