Downloading Synced Notes from iCloud
If your notes are synced to iCloud, you can restore them by turning on Notability's iCloud setting as described here.
Downloading Backup Copies of Notes
If Notability's Auto-Backup feature was on, you can download your backup copies into Notability as described here.
Restoring a Device to an iCloud Drive Backup
If your notes weren't synced to iCloud, your notes may have been included in an iCloud backup of your entire iPad.
- On your iPad, go to Settings > iCloud > Storage > Manage Storage.
- If there is a "BACKUPS" list, tap a backup to see whether it contains data from Notability.
If you have a backup with data from Notability, you can wipe your iPad and restore that backup as described here.