When you create a team in Microsoft Teams, you get a corresponding Office 365 group, which includes a group inbox and calendar in Outlook, a SharePoint site, and OneNote.
The Outlook group provides an email address people from outside the team can use to send email to the entire team. However, you can't post messages or view channel conversations from Outlook.
Note: With your help, people outside the team can also send an email directly to a specific channel.
You can access the associated SharePoint site from both Teams and SharePoint.
In Teams, just go to the team's General channel and click the SharePoint tab.