Phone technical 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 via telephone.

Customer support is a range of customer services to assist customers in making cost effective and correct use of a product. It includes assistance in planning, installation, training, trouble shooting, maintenance, upgrading, and disposal of a product. wikipedia.org

Social customer service is a form of customer support delivered via social media channels, such as Twitter, Facebook, and etc. that requires social agents to engage in conversations in a very public forum.

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

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

Software as a service (SaaS) sometimes referred to as "on-demand software", is a software delivery model in which software and associated data are centrally hosted on the cloud. SaaS is typically accessed by users using a thin client via a web browser. wikipedia.org

IT service management (ITSM or IT services) is a discipline for managing information technology (IT) systems, philosophically centered on the customer's perspective of IT's contribution to the business.