How to add your own domain to an O365 tenancy

So, you've taken the leap and set up your business with Microsoft 365 (formerly O365). You have access to powerful tools like Teams, SharePoint, and Exchange Online. There's just one small thing: your email address ends in @yourcompany.onmicrosoft.com.

While functional, it doesn't scream professionalism. The single most effective way to build brand identity and trust is to use your own custom domain for your emails and user accounts (e.g., info@jackdjd.com).

It might sound daunting, but Microsoft has made the process surprisingly straightforward. This guide will walk you through every step, from adding the domain to updating your user accounts.

Before You Begin: The Prerequisites

To ensure a smooth process, make sure you have the following ready:

1. Admin Access to your Microsoft 365 Tenancy: You'll need to be a Global Administrator to make these changes.

2. Ownership of a Domain Name: You must have already purchased a domain name (e.g., myawesomebusiness.com) from a domain registrar like GoDaddy, Namecheap, Google Domains, or similar.

3. Access to Your Domain's DNS Settings: You will need to log in to your domain registrar's website to add a few records to your DNS (Domain Name System) settings. This is how you prove to Microsoft that you own the domain.

   
   

Step 1: Navigate to the Domains Section in the M365 Admin Center

First things first, we need to get to the right place.

1. Log in to the Microsoft 365 Admin Center by navigating to admin.microsoft.com.

2. On the left-hand navigation pane, click 'Show all' if the menu is collapsed.

3. Go to Settings > Domains.

You'll see a list of your current domains. By default, you will only see your initial .onmicrosoft.com domain.

Step 2: Add Your Domain

This is the easy part.

1. In the Domains section, click the '+ Add domain' button.

2. A wizard will pop up. In the text box, type in the domain name you own (e.g., jackdjd.com).

3. Click 'Use this domain'.

Microsoft will now prepare to verify your ownership of this domain.

Step 3: Verify Your Domain Ownership

This is the most critical step. You need to prove to Microsoft that you are the legitimate owner of the domain you're trying to add. You do this by adding a specific record to your domain's public DNS settings. The recommended method is using a TXT record.

1. The wizard will present you with a few verification options. Select 'Add a TXT record to the domain's DNS records'.

2. Microsoft will now generate a unique TXT value for you. It will look something like this: $MS=msXXXXXXXX$.

3. Copy this value carefully.

4. Now, open a new browser tab and log in to your domain registrar's website (where you bought your domain).

5. Navigate to the DNS management section for your domain. This might be called 'DNS Management', 'Advanced DNS', or 'Manage Zones'.

6. You need to add a new record. The settings will be:

   • Type: TXT

   • Host/Name: @ (Some registrars may want you to leave this blank or type your domain name). The @ symbol typically represents the root of your domain.

   • Value/TXT Value: Paste the unique $MS=...$ value you copied from the M365 Admin Center.

   • TTL (Time To Live): You can usually leave this at the default setting (often 1 hour or 3600 seconds).

7. Save the record.

Important Note on DNS Propagation: DNS changes are not instant. It can take anywhere from 15 minutes to 48 hours for the new record to become visible across the internet, a process called propagation. Usually, it's quite fast.

8. Go back to the M365 Admin Center wizard and click 'Verify'. If the DNS changes have propagated, Microsoft will find the record and your domain will be verified! If it fails, wait 15-20 minutes and try again. Don't panic if it doesn't work on the first try.

Step 4: Connect Domain Services (Set up DNS Records)

Once verified, you need to tell Microsoft 365 how to handle services like email for your domain. This requires adding more DNS records.

The wizard will ask how you want to connect your domain services. You can let Microsoft add the records automatically if your registrar is GoDaddy or another supported partner. However, it's great to know the manual process.

Choose 'Add your own DNS records' to see what's required. Microsoft will provide you with the exact values for the following records:

1. MX (Mail Exchanger) Record: This is the most important one. It tells the world's email servers to deliver mail for your domain to Microsoft 365.

   • Type: MX

   • Host/Name: @

   • Value/Points to: A value that looks like <your-domain-com>.mail.protection.outlook.com.

   • Priority: 0 (or the highest priority available).

2. CNAME (Canonical Name) Record: This helps with autodiscovery, allowing email clients like Outlook to configure themselves automatically.

   • Type: CNAME

   • Host/Name: autodiscover

   • Value/Points to: autodiscover.outlook.com

3. TXT (SPF) Record: This is a Sender Policy Framework record. It helps prevent spammers from spoofing your domain name, improving your email deliverability.

   • Type: TXT

   • Host/Name: @

   • Value: $v=spf1 include:spf.protection.outlook.com -all$

Go back to your domain registrar's DNS settings and add these three records, just as you did with the verification TXT record.

Once you've added them, return to the M365 wizard and click 'Continue' or 'Done'. Again, allow some time for DNS propagation.

Step 5: Update Your User Accounts

Your domain is now fully connected! The final step is to switch your users from their old @yourcompany.onmicrosoft.com addresses to your new, professional domain.

1. In the M365 Admin Center, go to Users > Active users.

2. Click on the user you want to update.

3. In the pane that opens, go to the Account tab. Under 'Username and email', click 'Manage username and email'.

4. From the Domain dropdown menu next to the username, select your new custom domain.

5. Change the username if desired (e.g., from JSmith to John.Smith).

6. This will become their new sign-in name and primary email address. You can keep the old .onmicrosoft.com address as an alias so they don't miss any emails sent to it.

7. Click 'Save changes'.

Repeat this process for all your users.

You've done it! You have successfully added your own domain to your Microsoft 365 tenancy. Your team can now send and receive emails from professional, branded addresses, and your sign-in process reflects your company's identity. It's a foundational step in building a professional presence and getting the most out of the Microsoft 365 ecosystem.