Add a domain to Microsoft 365 (Exchange Online)

In Microsoft 365 for Business, you can add a company domain name you own so that your users can have email addresses branded with your company name. For example, if your company name is IT Society, owning the itso.work365.site domain and having your company name in your users' emails – such as alex@itso.work365.site – helps you brand your business and build trust with your customers.

You can easily buy a domain for your business if you don't have one already. Or if you already own a domain, you can easily add it.

This article about verify public DNS support Exchange Online includes MX, Autodiscover and SFP record.

Step 1: Get the DNS record.

Go to Microsoft 365 admin center > Settings > Domains > Select Domain > click Manage DNS.

Click Continue.

Checkbox Exchange and Exchange Online Protection.

Scall down and expand DNS record for email system include MX, CNAME and SPF record. get those records to create DNS or send to support DNS.

Step 2: Add DNS record.

Example file DNS record.

Example create DNS record.

Step 3: Verify DNS record status.

Go to website https://mxtoolbox.com and verify MX Lookup.

Verify CNAME Lookup.

Verify SPF Record Lookup (or using TXT record).

After ensures DNS record is valid go back to Domains > select domain and click Manage DNS.

Click Continue.

Ensure the checkbox Exchange and Exchange Online Protection and click Continue.

On Manage DNS show message Domain setup is complete.

The domain is status Healthy and then click Check Healthy.

Select DNS records.

Show status is OK all records.