Backup
An App backup can be created on app page
Go to Settings -> Backup
You can enable automatic Backup schedule for all apps
Go to Settings -> Backup
Select Auto mode: Backup
Select Day: Every day or a specific day
Select Hour
This is a bit more complex setup allowing you to have a secondary device as a copy of your primary device. Read the instruction
Backup is stored on a device file storage which located at /data/platform/backup
Device file storage (/data) is located either on an internal disk or on an external disk (if it was activated in Settings - Storage)