1. Servers having cPanel control panel
In the WHM console, click Backup Configuration, and scroll to the bottom looking for additional destinations. Select Amazon S3 in the Destination Type and Create new destination.
In the configuration page for this destination, give it a name and select the box that says transfer system backups to destination. (It says you should only do this if your connection is encrypted. Amazon S3 is an encrypted connection.)
Enter the name of the bucket, Access Key ID, and Secret Access Key.