Missing notes on iPhone: Apple dropped a fix for the bug
If your iPhone notes have disappeared, Apple has a fix for you.
In response to a bug that started appearing in the last week, Apple issued an official support note on its website to address the sudden, unexplained loss of Notes app content for some users.
iPhone fix for missing notes
According to Apple, here's what you need to do in order to get your notes back:
Open the Settings app and tap the part that says your name
Tap iCloud
Tap Notes
Toggle "Sync this device" on if it isn't turned on
Check Notes
This step-by-step guide should restore your notes. Apple also listed a contingency in case it doesn't: Restart your device and try again. Eagle-eyed readers may notice that this is almost exactly the same as the unofficial fix that circulated online last week.
The good news is that, no matter what, your notes should be stored in the cloud, so you didn't actually lose them. Just keep trying, and eventually, they should come back. If not, contact Apple support.