1) First login into your cPanel Web Hosting account with the Username and password
2) Click on Backup cPanel backup, backup website cpanel, cpanel hosting backup.
3) Now click on Generate / Download a Full Backup.
4) Select Home Directory in Backup Destination and enter your email address. others just leave blank and click Generate Backup.
5) Done! You just perform a full backup with cPanel Web Hosting. You will received a notification email once the backup is done.
6) Once the backup is ready, you can FTP into your Account to download the backup file. CPanel locate your backup file in your root directory (/home/username/) and CPanel backup filename normally look like this:-
backup-mm.dd.yyyy_hh-mm-ss_username.tar.gz
Note : You can also FTP your full backup file to your another FTP server (if you have more than 1 server). Just enter the Remote Server (FTP / SCP) which is the IP or domain name, Remote User (FTP / SCP) and Remote Password (FTP / SCP) in the Generate Backup page before you hit Generate backup button, your Backup File will be transfer to the remote server.

