[Permission Required: Account Administrator, Content Administrator, Editor]
A site may be archived when no further views and edits are required for it, but completely getting rid of the site is not an option.
You can refer to this article to delete a site or a template.
Visit to archived sites brings up a message similar to the one below:
Site properties such as analytics, URLs, team permissions, contents, designs, etc., are kept, though once archived, the site will not appear in the default search result view anymore.
To view or make a search for an archived site, click on the Archived folder at the bottom left editing panel of the dashboard (below the folders).
Archived sites cannot be edited, until they're unarchived.
To archive / unarchive a site:
Select the site from the dashboard.
Click More from the Site Details menu.
Click Archive / Unarchive.