Tecadmin published a tutorial showing you how to create a DMARC record for your domain.
Creating DMARC Record for Your Domain
What is DMARC? Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a technical specification for email authentication that was developed jointly by the Internet Engineering Task Force (IETF) and DMARC.org. DMARC allows email senders to create DMARC records in DNS that tell receivers what to do if the email being sent doesn’t pass either SPF
