A Web Designer is a person that creates and arranges the pages that make up a website. Web Designers often have to balance how a page looks versus how a web page functions, which can involve some compromises.
Of recent importance is website accessibility; this refers to creating web pages that are accessible to anyone, no matter what device they are using. Website accessibility also stresses the importance of making a website accessible to those with any kind of disability.
Most companies will hire a Web Designer based on their portfolio, so it is important to get some real world experience to showcase. These can be small, personal projects, volunteer projects for a school or community group, or projects someone paid you to complete.
A Web Designer may progress in seniority within the Web Design function. They may also progress within a marketing communications function, depending on their skills and interests.
A Web Designer is very different from a Web Developer. A Web Developer works more on the server side development, web server configuration, and web server security.