To remove a user's account, navigate to User Management on the left had side of the screen. Click on All Users. A new window will open displaying a list of all users; click on Remove User to permanently delete account.
Note: Not all users may have access to User Management settings. However any user can change their password by selecting the dropdown arrow next to your username in the top right hand corner. To do this, select the drop down arrow next to your username and select Update Your Profile, you will then be directed to your user profile where you can change your password or update your details. Click Update to save the changes.