For security reasons, user accounts cannot be duplicated. However, administrators can use an existing account as a basis for preferences and user roles:
User - Edit
Here you can change a range of options and preferences.
There are many roles available that can be used to allow or disallow access. Please take care when enabling high-risk roles.
These will dictate the visibility of certain widgets, and allow for customisation of news feed and other preferences.
This will affect email digests received.
The Subscriptions button will lead you to the Subscriptions Manager, where you can get a view of subscriptions that may be relevant to your new user.