If you need to share a campaign across accounts, or duplicate a public link from a campaign, follow these steps:
Set public visibility for a campaign
Within campaign actions you will see a Share link. Clicking it will display the modal to copy the public link for that campaign.
The link is valid as long as the Public Link toggle is true.
Copy a public campaign to your account
Just near the add new campaign button you have a “Copy” button that allows to input a public URL.
If the link is valid you will get a success message and the campaign will be added to your account.