Note: This is technical but essential.

SPF (Sender Policy Framework): An ID card for your domain.

DKIM (DomainKeys): An encryption key that proves no one tampered with the email in transit.

DMARC: A policy that tells Gmail what to do if an email fails the first two tests (Reject it or Quarantine it).

Teaching Point: Without setting these up in your DNS (Domain Name System), your emails will hit the spam folder.