You can format any text in your visual using the Font group on the Home tab. Begin by dragging your mouse to highlight the text you want to change.

Click on the large menu button
in the Font group to
select a font style and the smaller menu button
to
select a font size.
Click
to make the selected text bold;
click
to italicize the selected text;
and click
to underline the selected text.
The two buttons next to these three can alter text to be subscript or superscript, respectively.
Click
to change the color of the selected text.
You can also insert symbols while typing your text by clicking
.