Help:Template

What a template does

A template is a reusable piece of wiki content or formatting. In wikitext, a normal template is transcluded with double braces, for example Template:Example. Parameters can pass values into a template, such as Template:Example. The rendered result depends on the template's code and any nested templates or parser functions it uses.

Use an existing template

Before adding one, inspect its documentation and examples. Supply named parameters exactly as documented, and do not guess parameter names. A missing or misspelled parameter may be ignored or display incorrectly. Preview the page and check categories, links, references and layout. Keep the template call readable and preserve any required attribution or source information.

Build or change templates carefully

Template code can affect every page that uses it. Test proposed changes in an appropriate sandbox or test area if one is provided, and compare representative uses before changing a widely used template. Documentation should explain purpose, parameters and examples; see Project:Template documentation. Do not assume you can edit protected pages or that a particular testing extension is installed. For complex pages, see Help:Template limits.