Backup is a backup copy of your site. This means backup email, file, database. Just like when you photocopy an original document, it's the same with the site when you make a backup.
A properly made backup is the safest way for you to restore the site when something goes wrong as if nothing had happened.
In cPanel, you have a backup option that is best for you and that keeps your data the way it should be.
There are various add-ons and plugins as well as php scripts for making backups, but keep in mind that when that script is interrupted for any reason, the backup is not complete and you think it is.
If you want a proper backup, then do it through the option in cPanel.
