At the first time you enter GDPR setting (when your provider enabled GDPR),
You will have to approve the following: User Agreement, Privacy Policy and Backup Destination Information.
After approving the above, you will see
In order to save changes, you need to provide an encryption key.
The encryption key created on the first time you save settings after you approved everything.
PLEASE COPY THE KEY AND SAVE IT IN A SAFE PLACE.
This key might be required to restore data from backups, without it data might be lost.
When you choose Backup Type - Encrypted Backups you need to choose where you want to store your encryption key.
This should be used if you trust your hosting provider with your encryption key. Your hosting provider will be able to access your backups and perform actions for you (restore from backups).
CAUTION: If your encryption key is LOST, you will not be able to restore account backups to your account in case of data loss or disaster recovery.