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

In selling technique, a sales presentation or sales pitch is a line of talk that attempts to persuade someone or something, with a planned sales presentation strategy of a product or service designed to initiate and close a sale of the product or service. 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

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