Help:Editing
WikiText
MediaWiki makes use of a specialised form of editing syntax called Wikitext. This is essentially HTML with a few shorthands for including links, text highlighting, lists etc. Standard HTML and CSS will work as well, it will just be a little more verbose.
Examples of the various different types of Wikitext syntax can be found on the WikiMedia Meta Wikitext examples page.
It is also possible to display inline formulas: see the WikiMedia Meta page on 'Displaying a formula'.