Adding new users to my extranet account

I want to add a user account to my extranet. On the help, it is indicated to

  • Click on Account and then click on Create and manage users
  • Click on Add a user
  • Fill in the Name and Email fields for the new user you’d like to invite
  • Click on Next step: set access rights
  • Select the access rights you’d like the new user’s account to have, then click on Send invite

In my extranet, I don't have this menu. I only find a Contacts menu ?

Where is the menu Create and manage users ?