You can easily change the name of an Office 365 Group or Team through the Office Admin Portal or the Teams Admin Center. If you change the group or Teams name, it won’t automatically change the ID or email (SMTP) address associated with that group. In order to change that, you’ll need to use Exchange Online Powershell.
Change Office 365 Group or Team Email Address in Admin Center
This article has been updated in January 2022 since Microsoft has now added the ability to change a Team email address in the Microsoft 365 Admin Center (Thank you for the comments below with the update).
Go to the Microsoft 365 Admin Center
Go to Teams & Groups on the left > Active Teams & Groups
Search for and select the Teams group you want to edit
Click Edit under Aliases
To edit the primary email address, click the pencil icon next to the Primary Email Address and make the changes
You can also add multiple aliases
Click Save Changes
Once you edit the email address the old email becomes an alias which you can delete if you need to.