Setting up DMARC on Wix involves adding a TXT record in the advanced DNS settings with '_dmarc' as the hostname. The DMARC record should begin with 'v=DMARC1;' and include a policy tag (p=none, quarantine, or reject). Implement DMARC policies incrementally, starting with 'p=none' to monitor traffic via DMARC reports, then transitioning to 'p=quarantine' and 'p=reject' after verifying SPF and DKIM alignment. Utilize online tools to validate the DMARC record. Ensure you avoid common mistakes like incorrect syntax, missing SPF/DKIM records, and neglecting report monitoring. Be aware of stricter upcoming email authentication policies and coordinate with providers if using shared IPs. The benefits include improved deliverability and brand protection.