configuring company URL for Office365 webmail

There's a lot of misinformation I've found on creating a custom URL that goes to Office365 webmail.

You can always go to:

https://portal.microsoftonline.com

But if you want to create a custom URL with your company URL, you can simply create a CNAME record that points to Outlook.com

So if your domain name was xyz.com and you'd like mail.xyz.com to go to your Office365 webmail, you'd configure a CNAME record for mail that points to outlook.com