Administrators are able to share their own published content across portals given that they have the administrator role in those portals. This feature is commonly essential to those big organizations where they have separated portals for each team where in some instances, they need to share content across them.
In cases like this, the portal administrator can simply share content via 'Visibility and Access' Please see: How to share standalone learning items with portals
Why can't I see my shared content?
If you cannot see your shared content in the shared portal, you should check the portal's settings:
Click your initials at the top right-hand side of your dashboard
Go to Portal Content Selection - if you wish to show all shared content on your explore page, make sure 'All Shared' is ticked.
If you wish to custom select from the shared content, make sure you have added it to your custom selection
Course Sharing overview and Troubleshooting