Google/Gmail and other providers have required a DMARC policy for years, but some providers do not always enforce the policy, which is why some email will go through and some will get rejected.
DNS records (A, CNAME, MX, TXT, etc.) can be added, updated, and managed in cPanel -> Domains section -> Zone Editor.
Sample DMARC policy (replace example.com with your domain):
_dmarc.example.com -> v=DMARC1;p=none;
Note: Name server and DNS records cache at many levels (Internet provider, local router, local computer/device, etc.), so it may take a few hours (up to 24 hours) for name server and DNS changes to propagate to everyone on the Internet.
Please let us know if you have any questions or need further help.
