Default site collections in SharePoint Online:
When you create a new Office 365 tenant, It creates these site collections by default. If you go to the classic site collections page from SharePoint Online admin center, you’ll find these sites listed:
- The top-level site collection (or Root Site) at https://tenant.sharepoint.com
- https://tenant.sharepoint.com/portals/hub – Office 365 video hub
- https://tenant.sharepoint.com/search – The search center site for the tenant
- https://tenant-my.sharepoint.com – The My Site Host! OneDrive for Business sites will be using hosted under this URL.