Chat technical support is a form of technical support delivered via online chat. Online chat refers to a kind of communication over the Internet that offers an real-time direct transmission of text-based messages from sender to receiver. wikipedia.org

Customer service is the provision of service to customers before, during and after a purchase. wikipedia.org

Technical support or tech support refers to a range of services by which enterprises provide assistance to users of technology products such as mobile phones, televisions, computers, software products or other electronic or mechanical goods.

Customer retention agents work with existing customers to retain their business through probing, effective listening, building value, and overcoming objectives. wikipedia.org

Business Marketing is the practice of individuals, or organizations, including commercial businesses, governments and institutions, facilitating the sale of their products or services to other companies or organizations that in turn resell them, use them as components in products or services... wikipedia.org

Customer relationship management (CRM) is a widely implemented strategy for managing a company's interactions with customers, clients and sales prospects. wikipedia.org

Cold calling is the marketing process of approaching prospective customers or clients, typically via telephone, who were not expecting such an interaction. wikipedia.org

Office administration is a set of day-to-day activities related to financial planning, billing and recordkeeping, personnel, and physical distribution and logistics, within an organization. wikipedia.org

A subset of the field of commerce, business development comprises a number of techniques and responsibilities which aim at: wikipedia.org

A sale is the act of selling a product or service in return for money or other compensation. It is an act of completion of a commercial activity. wikipedia.org