Until you set up a domain of your own, your mail leaves from a platform address with your workspace name in front of it. That works, but your own address reads better and helps your deliverability.
You arrange it under Settings → Email → Sending. You will need access to your domain's DNS.
Under Register a sending domain, enter your domain and, if you like, a Display name: the name recipients see in front of the address.
Consider a subdomain such as mail.yourcompany.com rather than your bare domain. Its reputation then stays separate from the mail your colleagues send every day.
Once registered, the screen shows the records to put in your DNS, in three groups.
Proof of ownership. One TXT record showing that this workspace controls the domain. The signature records below prove somebody does; they cannot say who. This one says who.
Signature. Three CNAME records, which let a receiving server prove the mail really came from you. They are judged together, so two out of three is the same as none.
Return path. Two records on a subdomain, so that a bounce comes back to us rather than to the mail provider, and the address a recipient sees matches the one that answers for it. Note that such a subdomain may carry exactly one MX record. If something else already has one there, publish ours in its place. With two, verification never completes and the reason is not reported.
Each record shows what we can see of it: Found and accepted, Not found yet, Rejected or Could not be checked.
The check runs on its own. Most DNS providers publish within minutes, some take a few hours. If you would rather not wait, use Check status.
Until the domain is verified your mail still goes out, from the platform address. Nothing stops.
If a record disappears later on, the screen notices and sending falls back to the platform address until it is back.
A verified domain is not yet an address. Under Sending addresses you create the address your mail comes from: what goes before the @, and optionally a display name.
Without a sending address you cannot send a campaign. An address still used by a campaign cannot be removed; point that campaign at another address first.
This screen only covers mail going out. To receive mail on your own domain, set that up separately under Settings → Email → Receiving. The two use different subdomains and must not get in each other's way.
