Members are patrons who subscribe to Member Groups.
"Members" is the default term, but it is possible to change this in Administration > Organisation > Settings > Properties > SupporterName. If your system appears to use a different term in place of Members, treat everything said here about Members as applying to the term used in your system setup.
Your system may have multiple Member Groups. See Member Groups to learn how to create these.
Each operator can optionally be assigned the ability to manage Member Groups and the patrons that subscribe to these groups. An operator can manage multiple Member Groups. To see how to assign operators the ability to manage user groups, see Assigning Member Group Management to Operators.