In order to complete this you will need to have root access, WHM and SSH.

Step 1:

From cPanel WHM navigate to: Main >> DNS Functions >> Edit DNS Zone
Click on the domain for which you wish to enable wildcard and then click Edit.
At the bottom of the page add a entry like so:



Click Save and you are done here.

Step 2:

Connect to the server using ssh (putty for windows) and edit the following file:
/usr/local/apache/conf/httpd.conf

You can do this by running this command:
nano /usr/local/apache/conf/httpd.conf

Find the section containing your domain, it should look like this(in this example the domain edited is domain.tld):


You need to replace "ServerAlias www.domain.tld" with "ServerAlias *.domain.tld domain.tld", after you are done it should look like this:


Step 3:

Restart apache server from cPanel WHM, navigate to: Main >> Restart Services >> HTTP Server (Apache)

At this point Wildcard DNS should be functional.