New Portal or Department

New Portal or Department

I am following these instructions:   https://www.zoho.com/survey/help/enterprise-setup.html

When I go to Setup, there is a button that says "Create a New Department".
Is this the same as "Create a new Portal"?
If so, why don't Zoho's Help files get updated when changes are made?  

When adding and inviting users, do these users have to be CRM Plus users?

Thanks.