There is no backup tool included in the application.
In order to create a full backup of your Vtiger web site you need to export the database and download the files from the server.
The database backup can be generated through cPanel -> PhpMyAdmin. Open PhpMyAdmin and choose your Vtiger CRM database. Then click on the Export tab. Next, select all the tables. Also, check the Add DROP TABLE option fromStructure options and then click Go. You will download the sql dump file on your computer.
You can restore your backup by importing the mentioned sql file into a database for Vtiger. Open again your cPanel -> PhpMyAdmin and choose the vTiger database. Click on the Import tab, browse for the sql file on your PC and click Go. The database will be populated with the backup data.
After the database backup procedure continue with the files. The easiest option is to copy the whole folder with Vtiger from the server to your local PC using an FTP Client. Later, when you want to restore your old Vtiger just copy back the files from your PC to the server in the proper folder.