Master Page Designer Master Pages are templates you can create to control the look and feel of your content pages. If you want to create multiple pages that all share the same header, footer, navigation bar, and content elements, for example, Master Pages will make your work much easier. Simply select Master Page from the Add New Item menu of your project to create a new template, which will be saved with a .master extension. Include on this Master Page all the layout and content elements that will be common to your content pages. Once you have created your Master Page, you can apply the Master to new ASP.NET pages in your Web site. In the visual design view you can easily edit the unique portion of a single content page while seeing what the combined page will look like. Master Pages can be nested, and you can create different Master Pages to target different browsers. Create a single Master Page template to define the layout of multiple content pages.   Edit unique page content while seeing how it will look in the Master Page layout.