Why would I do this?

When a team is archived, the team becomes read-only, allowing the owner[s] and members to still access the content, including files (if also specified for archive). This will retain the team activity in channels, files and chats. It is possible to change membership of the archived team by adding or removing members.

This may be preferable to deleting a team which will result in a permanent loss of the team, chats, channels and associated files. After a short period of time, this deleted content cannot be restored.

Can I restore it?

Teams which have been archived can also be reactivated by the owners.

Further Information and Support

For more information and the process for archiving a Microsoft Team, please refer to the following article from Microsoft.