Automagic Dmarc on all cpanels

I am new to a full fledged WHM and not used to server config but getting there. I know how to add a dmarc per cpanel but can this be automated so that a new cpanel account automagically just has this? Really dont want to have to do this on 100 cpanel accounts. v=DMARC1;p=reject;pct=100;rua=mailto:postmaster@dmarcdomain.com Also it seems to be missing from my main server? Thanks!