How to recover my deleted notes

If you deleted the note less than 30 days ago, check the "Recently Deleted" folder in the Notes app.

To do this, open the Notes app and tap on the back arrow in the top left corner until you reach the main folder's view. Look for the "Recently Deleted" folder and tap on it. Here, you may find your deleted notes that are recoverable. Tap on "Edit" in the top right corner to select the notes you want to recover, then tap on "Move To" and select the desired folder to restore them.

If you deleted it from your Recently Deleted folder, there is no way to recover the note.

See: Delete and recover notes on iCloud.com - Apple Support