The Office 365 subscription comes with the onmicrosoft.com domain by default. If you want to use your own domain, it must be added to the 365 service using the service’s add domain function. You must own the domain, so make sure you have purchased the domain before following this guide.
Start by logging into the M365 admin portal (https://admin.microsoft.com/) with your admin credentials.
Use the navigation ribbon on the left side and select show all – settings – domains and click “Add domain”. This will start the add domain setup.
Enter the desired domain in the field provided for it and click “Use this domain”.
Leave the selection in ”Add a TXT record to the domain’s DNS records” and click “Continue”.
At this stage, domain ownership must be confirmed to Microsoft with verification. This is done by adding the TXT record indicated by the domain setup to the DNS records of your domain. Take note of the verification code that starts with MS=ms. If you have access to domain management, you can add the MS=ms verification code as a TXT record to your domain’s DNS records yourself or you can alternatively ask the domain administrator to do this by delivering the MS=ms verification code to the domain administrator. When the MS=ms verification code has been added to the domain’s DNS records, you can click the “Verify” button.
The next step is to add the DNS records that control e-mail traffic. Select “Add your own DNS records” and click “Continue”.
At this point, the M365 domain setup shows additional DNS records that should be added to your domain’s DNS records just as the MS=ms verification code was added. Take note of the MX, CNAME and TXT records. If you have access to domain management, you can add these records to your domain’s DNS records yourself or you can alternatively ask the domain administrator to make the changes for you by delivering the DNS records to the domain administrator. Once the information has been added, you can click “Continue”.
You have now successfully added the domain to the M365 service, click “Done” to exit the setup.
