In addition to the buttons you’ll see at the top of the posting window:
there are more options available for formatting.
“Common Markdown” is implemented:
A subset of BBCode is also available:
[b]strong[/b]
[i]emphasis[/i]
[u]underlined[/u]
[s]strikethrough[/s]

[url]http://example.com[/url]
[email]address@example.com[/email]
[code]\nx++\n[/code]
[spoiler]spoiler[/spoiler]
strong
emphasis
underlined
strikethrough
http://example.com
address@example.com
\nx++\n
spoiler
Some common HTML is also enabled if you want to try your hand at that.