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.

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

Lead generation, or lead gen is a marketing tool used, particularly in internet marketing, to generate consumer interest or inquiry into products or services of a business. wikipedia.org

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

Telemarketing (sometimes known as inside sales, or telesales in the UK and Ireland) is a method of direct marketing in which a salesperson solicits prospective customers to buy products or services, either over the phone or through a subsequent face to face or Web conferencing appointment

Email marketing is directly marketing a commercial message to a group of people using electronic mail email. wikipedia.org

A data entry clerk, sometimes called a typist, is a member of staff employed to type data into a database using a keyboard. The keyboards used can often have specialist keys and multiple colours to help them in the task and speed up the work. wikipedia.org

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