A help desk is a resource intended to provide the customer or end user with information and support related to a company's or institution's products and services.
Intercom make customer messaging apps for sales, marketing, and support, connected on one platform. Intercom's mission is to make business personal again.
Zendesk is a customer service software and support ticket system. Web-based help desk software used by 200000+ organizations worldwide. Free 30 day trial.