I’ve uploaded a file to iCloud three times, yesterday the third time. Access it through files Applic on iPhone.
The file is a legal document, only a 118KB PDF so doesn’t take up much space.
The first two times it stayed there for about 4 days, then after 4 days it vanished for no reason, I did not delete it.
I had it in a sent gmail about a year ago, but rather searching Gmail thought it would be more convenient on iCloud.
I’ve also this time put it on drop box, goggle drive and a hard copy saved to notes.
If it disappears off iCloud for a third time, I will no longer have faith in storing stuff there, though all my passwords are on it through iPhone passwords and that hasn’t missed a beat.
I also backed up iPhone yesterday, then checked and file still there, so it’s not space when phone backs up.
Edit 3.5GB of 5GB used.