Operating systems today offers us a wide range of font options, such as, type, style and size. Ubuntu Linux lets you change the fonts in an easy way. There are five types of fonts which falls in category of Desktop Fonts. These are Application Font, Document Fonts, Desktop Fonts, Windows Title Fonts and Fixed Width Fonts.
To change fonts in your Ubuntu, load Appearance box from System > Preferences > Appearances.
Now, click at Fonts Tab in appearance box.
Here you will be able to see all types of fonts. The procedure to change all types of font is the same. Click at the font you want to change, Pick a Font will be displayed.
Now, select Font family, style & size, and Click OK to apply it. An option to change the Font rendering settings is also available. There are a total of four types of font rendering settings, select any one and click Close to apply it. Enjoy!