Deactivate users in the system

When you see a list of users
you can either click an Edit icon on the right or use search and enter e.g. user's last name. When you click the icon, you can modify user's data and change the status to "Inactive".

Click the "Save" button. As a result, the user will lose access to the system and disappear from the lost of active users. 
The user will appear on the list of inactive users. In order to view this list, you need to select a filter Inactive users at the top of the screen.
Obviously, not only won't the user be listed as active but also won't have access to the system. When he attempts to login, a message "Invalid username or password" will be displayed. 
In order to activate again the employee, got to the admin panel and select "Permissions" and "Users". Use the filter Inactive users at the top and press Restore on the right side of the screen. 
When you click on the icon, a pop-up window will appear and you will have to confirm your decision. Click OK and the user will again appear on the list of active users and will have access to the system.