What is a domain?
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Check the Domains FAQ if you don't find what you're looking for.
A domain is a unique name that appears after the @ sign in email addresses, and after www. in web addresses. It typically takes the form of your organization's name and a standard Internet suffix, such as yourbusiness.com or stateuniversity.edu.
Using a custom domain like rob@contoso.com with Microsoft 365 can help build credibility and recognition for your brand.
Choose the experience that's best for you:
Buy a new domain:
Use Microsoft 365 to buy a new domain - we'll set everything up. Learn more.
Use a domain you already own:
If you already own a domain like you@yourcompany.com you can add it and start using OneDrive and Microsoft apps right away. You'll need to take a few minutes to setup mail and Skype for Business.
Tip
Not sure where your domain is registered? - Get help finding your domain registrar
Use a Microsoft domain for now:
You can use a Microsoft domain like yourcompany.onmicrosoft.com to sign in for now and add a custom domain later.
Important
If you select this option, the name you enter for your .onmicrosoft.com domain will be used in all your SharePoint and OneDrive URLs. You might not be able to change this name, so make sure it's spelled correctly if it's the name you want to use from a branding perspective.
Feeling stuck?
Call Microsoft Support - Get help setting up a domain
Related content
Buy a domain (article)
Add a domain to Microsoft 365 (article)