Client-side coding languages like HTML, CSS, JavaScript, PHP, and XML are used to build the structure and design of web pages. HTML defines the structure, CSS handles styling and layout, and JavaScript enables dynamic user interaction. The code is interpreted by browsers line-by-line. Web pages are created by writing HTML structure, adding CSS design, testing and refining as needed, and saving all files together in a folder for the browser to access and display the rendered page. Popular code editors include online options like Scratchpad and offline editors like Notepad++ for Windows and Brackets for Mac.