One way to do this would be to use the the Backup utility included with the Hosting Control Panel provided by your hosting provider.
Joomla! users may instead prefer to use a Third Party Extension like Akeeba Backup.
We like Akeeba Backup PRO.
About this Article
Akeeba Backup PRO includes lots of setting options for you to choose from.
Most users will not need to make significant settings changes, but if you do then be sure to refer to the developer's User Guide before proceeding.
Creating a Backup Archive is almost intuitive.
There are however a few basic settings tweaks you could usefully make before creating your first Backup Archive.
FIRST, purchase the Akeeba Backup PRO subscription.
Useful Setting Tweaks
Restoring an Archive created using Akeeba Backup
Be aware before starting to use Akeeba Backup that to restore a website from an archive created using it requires the use of an extension called KICKSTART.
This extension is provided FREE by the developer.