First you have to know what your site consists of and what should be backed up. These instructions explain how to back up a site composed of files and databases:
1. Files backup
An alternative way to backup the content of the public_html/ folder is to create an archive of its content through the cPanel --> File manager and download the generated file on your local PC again through the File manager or using an external FTP client.
2. Database backup
For detailed instructions on how to backup (export) your MySQL database, please check our MySQL tutorial.
You can also back up your entire account using the Create Backup option in cPanel. In order to be able to create full cPanel backup your hosting account should be with size less than 500MB. From the same tool you can download separate backups of the databases.
SiteGround offers the best cPanel hosting package. With it keeping backups of your website will be easier than ever.