Typography is the art and technique of arranging and designing text, which can help create a visual hierarchy, a clear structure, and a readable and appealing user interface. It's important to understand the basics of typography, such as typeface (a collection of fonts with a common design and style), font (a specific variation with a defined weight, size, and style), font family (a group of fonts that belong to the same typeface), font size (measurement of how large or small a font is), font weight (measurement of how thick or thin a font is), and font style (modification that adds emphasis or variation). To use typography in your user interface design, you should choose your fonts wisely - no more than two or three fonts - making sure they are compatible and complementary. Additionally, use font hierarchy to organize fonts according to their importance, function, and meaning. Finally, apply font readability to ensure that your fonts are easy to read for all users. You can use online tools like Google Fonts, Font Pair, Readable, or Hemingway to help with this process.