Linking to existing Wikipedia pages is done by placing doubled square brackets around the name of the page. Thus, [[Wikipedia]] produces Wikipedia. A useful expansion of this is done by separating what you want linked, from what you want displayed, with a pipe character ("|"), to create a "piped link". Thus: [[Wikipedia|encyclopedia]] produces encyclopedia, with the displayed text linking to the article, Wikipedia. You can link to internal sections of pages in this way: Wikipedia#name of internal section of that article. By contrast, for external links: https://www.example.org produces https://www.example.org; [https://www.example.org] produces [1]; and [https://www.example.org example] produces example. For more information, see Help:Link and please consider taking a tour through the Wikipedia:Tutorial. Hope this has helped.
