Though you can do a great deal with SharePoint using just a web browser—gain access to the site settings and SharePoint central admin (and appropriate permissions of course)—if you need to make significant customizations, you will need a more powerful tool. Microsoft provides excellent tools for power users, designers and developers to extend and customize all aspects of SharePoint.
SharePoint Designer is a free, lightweight development tool, targeted primarily at SharePoint power users, designers, and developers, to customize SharePoint sites and create SharePoint applications without the need to write .NET code (though a good working knowledge of HTML, CSS, and JavaScript is definitely required for customizing the SharePoint user interface).
A user can customize almost every aspect of a SharePoint site collection or site, including creating new, or modifying existing lists, columns, content types, master pages, site groups, and so on. One...