Let’s start with some definitions:
Web design encompasses many different skills and disciplines in the production and maintenance of websites. The different areas of web design include web graphic design; interface design; authoring, including standardized code and proprietary software; user experience design; and search engine optimization.
Web development is a broad term for the work involved in developing a web site for the Internet (World Wide Web) or an intranet (a private network). Web development can range from developing the simplest static single page of plain text to the most complex web-based internet applications, electronic businesses, and social network services. A more comprehensive list of tasks to which web development commonly refers, may include web design, web content development, client liaison, client-side/server-side scripting, web server and network security configuration, and e-commerce development. Among web professionals, “web development” usually refers to the main non-design aspects of building web sites: writing markup and coding.
A virtual assistant (typically abbreviated to VA, also called a virtual office assistant) is generally self-employed and provides professional administrative, technical, or creative (social) assistance to clients remotely from a home office.