I can no longer find the User Management section. Previously I would click on the cog wheel in the upper right of any Jira screen & one of the options was "User Management". That is where I would invite & manage users. The User Management option is no longer showing when I click on the cog wheel. 
This is where I would add, look up people, edit & fix profiles for Jira in general. When I look up people in a specific project, I do not have the ability to see or edit their profiles.
Yes, I am an administrator.