Usually, Texinfo changes the font to mark words in the text according to
what category the words belong to; an example is the @code command.
Most often, this is the best way to mark words.
However, sometimes you will want to emphasize text without indicating a
category. Texinfo has two commands to do this. Also, Texinfo has
several commands that specify the font in which TeX will typeset
text. These commands have no affect on Info and only one of them,
the @r command, has any regular use.