When you create a new team in Microsoft Teams, by default Teams will create a new Office 365 Group for you that is linked to the team. The name of the Office 365 Group is automatically determined based on the name you give your team. In other words: it’s not necessarily exactly the same as your team name, so it might not be the name that you want. The same goes for the email address that is created for this Office 365 Group.
Why would that be a problem? To me it’s about the email address that comes with the Office 365 Group (and therefore the team): I would like this email address to be as short and convenient as possible for the team, since it’s also often used as a distribution list when you’re sharing something from other applications.
So how do you get around that? Currently the only way is to create your Office 365 Group first. If you do this from the Office 365 Portal, you will see a field where you can fill in the desired email address – only the part before the ‘@’ sign. After you enter it, Office 365 will tell you right away if that address is available or not.
NB: you cannot alter the email address of an existing O365 Group through the UI. That can only be done with PowerShell, using the Set-UnifiedGroup command.
Once you’ve created the desired O365 Group and email address there, you can go to Microsoft Teams and create a new team based on that existing O365 Group.