DMARC records provide instructions to receiving mail servers on how to handle emails that fail SPF or DKIM checks. To add a DMARC record:
Log in to your domain registrar's account. Navigate to the DNS settings section. Create a new TXT record. The name will be _dmarc and the value will follow a format like: v=DMARC1; p=none; rua=mailto:dmarc-reports@example.com Save the changes and allow some time for the DNS to propagate.