I have installed Magento 220.127.116.11 and in my log folder there aren't system.log and exception.log files.
To get error log file I enabled on this menu Configuration >Developer > Log Settings > Enabled=Yes
and created /var/log folder and set the permission 777.
There is no file on the var/log folder
Can I know the reason why the error log file is not created and how to solver?
Enabling logging in not enough. Both system.log and exceptions.log are created once you have something to put there -- usually when something goes wrong. In perfect world neither of those files has reason to exist.
Error logs are always created in case something goes wrong, just make sure you have done:
1. Enabled logging from Magento Configuration.
2. 777 permission has been given to /var