Goodnotes: How to Back Up and Restore Data Manually in GoodNotes 5
1. Tap the gear icon in the top-right corner of the Library view.
2. Select Settings then Backup Data.
3. When the backup process is done, the Share Sheet will show up and you can select a destination or any app to save the backup file (in .zip) to either iTunes, iCloud, supported cloud storage through the Files app, an external app, and so on.