Short link: exact.help/How-to-edit-DNS-zones
This guide will go over how to edit DNS zones for Cpanel hosted domains.
This action is done within your WHM from there type in the search bar "edit DNS zone".
Type in the domain name, select the domain and then click edit at the bottom of the page.
From the next screen, you'll see a list of DNS associated with Cpanel and the domain. Scroll towards the bottom to find the new fields for entry.
I've included an example template for a CNAME in the image below don’t forget the trailing period!