Microsoft 365 Groups are a shared workspace for email, conversations, files, and events where group members can communicate and collaborate. For example, you can create a group for your team and invite other Microsoft 365 users to join the group, and then share documents, conversations, meeting notes, and OneNote information related to that specific group. Note: This feature requires that you have an Microsoft 365 account.
For additional information see https://its.uiowa.edu/services/microsoft-365/microsoft-365-groups