Navigate to Setup > System > Users. Here you can see the list of all existing users. Administrators have a number of functionalities that they can use from the following page.
Administrators can use user list to add, activate, deactivate, and delete users by using respective buttons in the top right corner of the window.
Number column shows status of each user. Green check mark indicates that user is active ( user can access the P4W system and consumes one license), while red stop sign mean user is deactivated (cannot use the system and does not contribute to the total pool of licenses)
Finally, administrators can impersonate (login as another user without a password) any user to verify permissions and setup screen layouts. To impersonate the user click the chain icon of the desired user as shown below.
Notice: Only administrators can use features listed above. Even a module that has access to the 'System' directory cannot alter the contents of the user list.