In TC9 we can use HTML (Hyper Text Markup Language) code inside text fields. This makes that we can use styling, like different font sizes, (background) colors, borders and more, in one and the same text field.
HTML is the language that is used on the WWW to render web pages. Luckily it is easy to experiment and to learn with the help of this wonderful website w3schools.
If you prefer to use a code editor … notepad++ is free and it is a very nice one.