DKIM, explained
DKIM (DomainKeys Identified Mail) adds a digital signature to every email you send from your domain. The receiving mail server looks up a public key you publish as a DNS record and checks the signature against it. If it matches, the server knows the message was sent with your domain's permission and was not altered on the way.
It matters for sales email because inbox providers use it, together with SPF and DMARC, to decide whether a message is trustworthy. Email that fails these checks is more likely to land in spam or be rejected, and a domain without them is easier for someone else to impersonate. For a team sending quotations and follow-ups, that is the difference between being read and being ignored.
Setting DKIM up is a one-time task: your sending service gives you DNS records to add at your domain registrar, and after they are verified, outgoing mail is signed. If you change sending services later, publish the new service's DKIM records before switching, so no message goes out unsigned. DigiPix Flow sends CRM email from your own domain once its DNS records are in place.