The font isn't changed in the wiki software, it's changed in your own computer and browser. There isn't any font specified in the web pages beyond the general 'serif' or 'sans-serif'. The wiki articles are all marked as sans-serif, so the font you get will be whatever you set your browser default to.
You can specify a different font to be used on your articles if you wish. Just put this code before the text
<span style="font-family: Batang, Serif">
and end the section with </span>
If you are covering several paragraphs with the font, try using <div... and </div> instead of <span... and </span>
However, the Batang font won't be downloaded by the browser. If the user doesn't have that font installed already, then they browser will default to whatever happens to be available on the users machine. So it's usually a good idea to name more than one font. Just list them in order of preference, separated by a comma. Multi word named fonts should be surrounded by quot marks. Pick fonts that are popular and commonly installed rather than the most beautiful.
