All those registered with the platform are called members.
You can find an overview of all members under Setup.
Find a member by sorting by surname, organization, or first name.
Under Edit, webmasters can directly see an overview of all the member-related information they are able to edit.
If you just want to know how many active members there are and how much space is left for adding new members, go to Setup and then Overview.
Active members are those who are able to use the platform. This is not the same as online members, which indicates who is currently online – in the Members widget, for instance.