How do I use my assigned domain email in Outlook 365?

1. Verify domain ownership:
Log in to the Microsoft 365 Administrator Center and navigate to Settings > Domains.
Add and verify the domain name, and follow the prompts to add DNS records (such as TXT or MX records).
2. Set the domain mailbox as the primary mailbox:
In the Microsoft 365 Administrator Center, navigate to Users > Active Users.
Select the account, click “Manage Usernames and Emails”, and set the domain mailbox (e.g. email address removed for privacy reasons) as the primary mailbox.
3. Configure Outlook 365:
Open Outlook 365 and click “File” > “Account Settings” > “Account Settings”.
Select your Microsoft 365 account and click “Change” to change the email address to a domain email address.
Save the changes and restart Outlook.
4. Check the auto-discovery settings:
Ensure that the auto-discovery records for the domain are properly configured.
Use command prompt to check auto discovery: nslookup -type=srv _autodiscover._tcp.yourdomain.com
If not configured, contact the domain registrar or IT administrator to add the record.
5. Try to test the mailbox function: send a test email to the domain mailbox and check whether it is received normally.
Send an email using Outlook 365 and check if the From address is correctly displayed as the domain mailbox.