The Archive Wizard allows you to remove an employee from view, as well as removing their information any clock they are enrolled on.
This is not permanently deleting the employee. That can be done once the employee has been archived, but it's generally a good idea to retain their information for the purposes of record-keeping.
To start the wizard, select the employee you wish to archive and click the 
icon on the toolbar. This window will pop up:
Select the dropdown box to enter a leaving date; the X button clears whatever you might have selected. Entering a leaving date is not required to proceed.
Click Next and you'll see:
This setting removes all of the employee's information (this includes clockings) from any devices they are assigned to. Note: this does not permanently delete their templates but simply removes them from the clock/s.
After this process has been completed you'll get a popup stating how it went, with either a success or failure message for each clock.
Click Next again to go to the final step:
Clicking 'Move to Archive' will remove the employee from active view in Focus, but they will still be visible via the System menu > Archive.