If you want to set up and use email, and/or create a website for your business you’ll need a domain. A domain is a unique name that appears after the @ sign in an email addresses, and after www. in web addresses. It usually takes the form of your business's name and a standard internet suffix like .com or .co.uk.
Using a custom domain can help build credibility and recognition for your brand.
As part of your O365 purchase, you can either transfer your existing domain to us, or buy a new one.
To transfer your existing domain, follow the I already have a Domain process.