Each separate UI Text component can have its own color, size, boldness styling, and so on. However, if you wish to quickly add a highlighting style to the part of a string to be displayed to the user, you can apply HTML-style markups. The following are examples that are available without the need to create separate UI text objects:
- Change the font to Xolonium-Regular
- Embolden text with the b markup: I am <b>bold</b>
- Italicize text with the i markup: I am <i>italic</i>
- Set the text color with hex values or a color name: I am a <color=green>green text </color>, but I am <color=#FF0000>red</color>
You can learn more by reading the Unity online manual's Rich Text page at http://docs.unity3d.com/Manual/StyledText.html.