From ICT Register Wiki
If you have standard texts you want to include on several pages, the MediaWiki template feature comes into play.
Creating a template
Template names are prefixed with Template:, you create them like any other wiki page.
Using a template
Templates are wiki pages which can be used in other pages in three ways:
{{Name}} includes the content of the template at the moment the page containing it is fetched "[[Template:Name]]".
{{subst:Name}} inserts the content of the template into the code of the page in a form that is editable normally "[[Template:Name]]" after you have saved your text.
{{msgnw:Name}} when the page containing it is fetched, includes the template in a form that displays it as raw wiki syntax, like <nowiki> does