What causes the enigmatic disappearance of notes, and how can one retrieve their lost thoughts?
First, check your settings.
The notes app’s proper configuration serves as a strong basis for the first defense. Missing notes were occasionally simply obscured by alterations made to iCloud or email settings. What to do is as follows:
Check your account’s settings:
Navigate to Accounts under Settings > Mail.
Check to see if the Notes toggle is turned on for each email account you use.
For every linked account (such as Gmail, Yahoo, etc.), do this. Your app will appear empty and your content may not sync properly if Notes is not enabled.
Examine the folder that was recently deleted:
To view the Folders list, launch the Notes app and tap the back arrow.