manpage - `audit.conf` man page is missing

I have installed Ubuntu 14.04 latest version, and when I do man audit.conf it returns No manual entry for audit.conf but I need it...

I assume you are looking for man auditd.conf, not man audit.conf?

In a comment, you say

man auditd.conf

also prints No manual entry for auditd.conf, right?
That means, the package that contains it is not installed;

It's easy to guess, but let's find which package we need systematically:

$ apt-file search auditd.conf
auditd: /etc/audit/auditd.conf

auditd: /usr/share/man/man5/auditd.conf.5.gz

So, the package auditd contains the file auditd.conf - and the man page for it.
Install it with

sudo apt-get install auditd

Now,

man auditd.conf

should work.