You can set the font name and size by using the \f and \fs statements. The name is set by using a font number specified in the \fonttbl statement. The size of the font is specified in half-points. The following example sets the text to 10-point Times New Roman (if the \fonttbl statement matches the example in Declaring Character Set, Fonts, and Colors):
\f0\fs20
Once you set the font name and size, the settings apply to all subsequent text up to the next \plain statement or until you change the name or size by using the \f or \fs statement again. The \plain statement resets the name and font to the defaults. The default font name is as set by the \deff statement; the default font size is 12 points.