We use zendesk at work for internal tracking, and it works great for us. For end users, it's just a magic email address. Assuming your organization is functional, I can't recommend enough having one email address for any issue. Need something purchased? Is the toilette backed up? Need a network jack activated? Send an email and get back to work, don't try and figure out who's in the office that day, knows what you need and is available to help you.