Set up a sending mailbox on a subdomain

Your company mail runs on yourcompany.com, but cold outreach should never send from there. The trick: your existing Google Workspace or Microsoft 365 can carry MORE than one domain. You add outreach.yourcompany.com to the account you already pay for, create a mailbox on it, and your main domain's reputation never touches a cold email.

Google Workspace, about 15 minutes

1. Add the subdomain. Go to admin.google.com → Account → Domains → Manage domains → Add a domain. Type outreach.yourcompany.com and pick Secondary domain. Google shows a TXT record to prove you own it. Add that record at your DNS provider (the clicks for every provider), then press Verify.
2. Create the sending mailbox. Directory → Users → Add new user. In the email field, open the domain dropdown and pick the new subdomain, so the address reads like jordan@outreach.yourcompany.com. This is a normal licensed seat.
3. Point mail records at Google. On the SUBDOMAIN, add the MX record Google shows you (so replies land), plus SPF: a TXT record with v=spf1 include:_spf.google.com ~all.
4. Turn on DKIM. Apps → Google Workspace → Gmail → Authenticate email. Pick the subdomain, generate the key, publish the TXT record it gives you, then press Start authentication.
5. Check it. In the Desk portal, run the deliverability check on the subdomain. SPF, DKIM, DMARC, and MX should all read found (DMARC can inherit from your main domain). Then press Connect Gmail and sign in as the new mailbox.

Microsoft 365, same idea

1. Add the subdomain. Microsoft 365 admin center → Settings → Domains → Add domain. Type the subdomain, verify with the TXT record it shows, and let the wizard list the DNS records.
2. Add the records. The wizard gives you the MX record, SPF (v=spf1 include:spf.protection.outlook.com -all), and two CNAME records. Add them at your DNS provider.
3. Turn on DKIM. Go to security.microsoft.com → Email authentication settings → DKIM, pick the subdomain, and enable signing. It asks for two more CNAME records (selector1 and selector2). Add them, then enable.
4. Create the mailbox. Admin center → Users → Add a user, and pick the subdomain for the address. Assign a license with Exchange email.
5. Check and connect. Run the Desk deliverability check on the subdomain, then press Connect Outlook and sign in as the new mailbox.

The separate-domain alternative

Some teams prefer a whole separate domain (like get-yourcompany.com) instead of a subdomain. It costs about ten dollars a year at any registrar and gives maximum separation: even the subdomain association with your main name is gone. The setup is identical, add the new domain to your existing Google Workspace or Microsoft 365 and follow the same steps. Subdomain or separate domain are both fine. Sending from your MAIN domain is the only wrong answer.