How do I change the default domain in Office 365? Print

You must have at least one custom domain that you've added to Office 365 before you can choose a default domain.

1. Sign in to Office 365

2. Open the Domains page

3. On the Domains page, choose the domain you want to set as the default for new email addresses.

4. Click Set as default.

You cannot change the name of your initial .onmicrosoft.com domain.