You can simply switch to the 'editing' view to see the markup that is used to create the following basic text-formatting examples.
!heading = small heading with text 'heading'
!!heading = medium heading with text 'heading'
!!!heading = large heading with text 'heading'
''text'' = prints 'text' in italic.
__text__ = prints 'text' in bold.
{{text}} = prints 'text' in monospaced font.
* text = makes a bulleted list item with 'text'
# text = makes a numbered list item with 'text'
---- = Make a horizontal ruler. Extra '-' is ignored.
\\ = force a line break
[link] = creates a hyperlink to an internal WikiPage called 'Link'.
[this is also a link] = creates a hyperlink to an internal WikiPage called
'ThisIsAlsoALink'.
[click here|link] = creates a hyperlink to an internal WikiPage called
'Link', but displays the text 'click here' to the
user instead of 'Link'.
[1] = Makes a reference to a footnote numbered 1.
[#1] = Marks the footnote number 1.
[link] = creates text '[link]'.