Your domain is part of your identity.
A business email address ties a conversation to your own domain. The setup also needs a way for receiving services to distinguish legitimate sending from a message that only claims to come from your organization.
Domain authentication is part of that foundation. It does not guarantee that every message reaches an inbox, but it gives receiving systems information they can use when evaluating your mail.
Three records with different jobs.
SPF describes which sending systems are authorized for a domain. DKIM adds a cryptographic signature that can be checked using a public key published in DNS. DMARC builds on authentication and alignment to define a handling policy and reporting.
Configure these records for the services that actually send on behalf of your business. That may include your mail platform and, separately, transactional mail or approved business tools. Keep the inventory up to date as those services change.
Treat email as an operating system.
Use appropriate mailbox permissions, secure access and a process for adding and removing team members. Make sure the people supporting the service know where domain settings and recovery procedures live.
Review changes carefully when moving email providers. Domain records, existing mail, user access and connected applications all need attention. A guided setup helps turn these pieces into a service your team can rely on.