Typing is the process of writing or inputting text by pressing keys on a typewriter, keyboard, cell phone, or a calculator 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.

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