A user cannot be deleted for compliance purposes, but can be deactivated. If you inactivate a user, they will remain on the Users page with an inactive status. The inactive user will not be able to log in to the system and will no longer be assigned to any job. Previously recorded actions for that specific User will remain logged in the system.
To deactivate a user, click Admin > Users, then click the ⋮ menu on the far right of the user's name, and then select Deactivate.