Forum:How to enable macrons?

Several wikis—Particularly Japanese based ones—have enabled macrons (ō) and have added them to the general editing bar (forgive me, but I have no idea what it is called). If not that, by pressing the "more" button, an option to put a macron appears. I believe this has something to do with MediaWiki, but I'm inexperienced. How can I enable this feature? Contribs ~ Yuri Bara ~ (talk)      00:31, July 16, 2014 (UTC)