Finalise is Huddle's way of archiving, in that it locks a Workspace and saves only the very latest version of any files. To Finalise a Workspace, go to Account Settings from your Dashboard, and then Workspaces per the screenshots below:
Once in Workspaces, you'll be able to Finalise any particular Workspace that you're a manager of. This will delete all old versions of documents, saving only the most recent versions. It will also close any tasks open for team members. Documentation will be archived and is retrievable, but the project is effectively closed. If you prefer to just stop access to the project for a while, then re-activate, just click 'Lock' on this page and everything will be paused. If you want to delete all documents, users and the Huddle Workspace in its entirety then click 'Delete'. Note that users will not be deleted from Huddle, just the Workspace that you're deleting.