WordPress is web software you can use to create a beautiful website or blog. We like to say that WordPress is both free and priceless at the same time.

The core software is built by hundreds of community volunteers, and when you’re ready for more there are thousands of plugins and themes available to transform your site into almost anything you can imagine. Over 60 million people have chosen WordPress to power the place on the web they call “home” — we’d love you to join the family.

Themes are often used to change the look and feel of a wide range of things at once, which makes them much less granular than allowing the user to set each option individually. For example, you might want the window-borders from a particular theme, but installing it would also alter your desktop background.

One method for dealing with this is to allow the user to select which parts of the theme they want to load, for example in Windows 98, you could load the background and screensaver from a theme, but leave your icons and sounds untouched.

Microsoft Windows supported themes since Windows 98. This operating system and its successor, Windows ME, came with themes that customized desktop backgrounds, icons, user interface colors, Windows sounds and mouse cursors. A separate application package called Plus! for Windows 95 added the same features to Windows 95. Windows XP themes expanded Windows theme support by customizing the visual style of the user interface. This feature was carried over to Windows Vista, which added Windows Aero, but was removed again withWindows 8. Third-party apps such as Window Blinds, TuneUp Utilities and Desktop Architect enhance theme capabilities.Linux operating systems may support themes depending on their window managers and desktop environments. IceWM uses themes to customize its taskbar, window borders, and time format. WindowMaker can store colors for icons, menus, and window-borders in a theme, but this is independent of the wallpaper settings. GNOME and KDE use two independent sets of themes: one to alter the appearance of user interface elements (such as buttons, scroll bars or list elements), and another theme to customize the appearance of windows (such as, window borders and title bars).Mac OS is does not natively support themes. Third-party apps such as Kaleidoscope and ShapeShifter may add this.

For the web designer, when each web page comes from a web template, they can think about a modular web page structured with components that can be modified independently of each other. These components may include a header, footer, global navigation bar (GNB), local navigation bar and content such as articles, images, videos etc.

For programmers the template language offers a more restricted logic, only for presentation adaptations and decisions, not for complex (business model) algorithms.^{[citation needed]}

For other members of the “site team”, a template system frees webmasters to focus on technical maintenance, content suppliers to focus on content, and for all of them more reliability.

Moreover, it has the following advantages to its use:

• Ease of design change: presentation variations on templates are “content invariant”, meaning a web designer can update the presentation without wider infrastructural preoccupations.^{[citation needed]}
• Ease of interface localization: menus and other presentation standards are easy to make uniform, for users browsing on the site.^{[citation needed]}
• Possibility to work separately on design and code by different people at the same time.^{[citation needed]}

One difficulty in evaluating separation of concerns is the lack of well-defined formalisms to measure when and how well it is actually met.^[2] There are, however, fairly standard heuristics that have been borrowed from the domain of software engineering. These include ‘inheritance’ (based on principles of object-oriented programming); and ‘templating and generative programming’, (consistent with the principles of MVC separation).^[3] The precise difference between the various guidelines is subject to some debate, and some aspects of the different guidelines share a degree of similarity.^[4]

WordPress has a web template system using a template processor.

WordPress users may install and switch between themes. Users to change the look and functionality of a WordPress website or installation without altering the information content or structure of the site. Themes may be installed using the WordPress “Appearance” administration tool or theme folders may be uploaded via FTP.^[9] The PHP, HTML & CSS code found in themes can be added or edited for providing advanced features. Thousands of WordPress themes exist, some free, and some premium (paid for) templates…

One very popular feature of WordPress is its plugin architecture which allows users and developers to extend its abilities beyond the core installation. WordPress has a database of over 26,000 plugins,^[10] each of which offers custom functions and features enabling users to tailor their sites to their specific needs. These customizations range from SEO (Search Engine Optimization) enhancers, to client portals^[11] used to display private information to logged in users, to content displaying features, such as the addition of widgets and navigation bars.

Prior to WordPress 3.0, WordPress supported one blog per installation, although multiple concurrent copies may be run from different directories if configured to use separate database tables. WordPress Multi-User (WordPress MU, or WPMU) was a fork of WordPress created to allow multiple blogs to exist within one installation but is able to be administered by a centralized maintainer. WordPress MU makes it possible for those with websites to host their own blogging communities, as well as control and moderate all the blogs from a single dashboard. WordPress MU adds eight new data tables for each blog.