Generally there are 2 ways:

1. The easy way - use preset fonts selections that we provide

We provide font selections that go well with our theme. When customizing a theme, select the fonts that you want to use. You can also select the font size, weight and letter spacing.

From the Menu on the Theme Customizer click Design > Fonts.

2. The hard way - use whatever web font you want

ArtStation Pro offers CSS overrides. This enables you to use the @import statement to import any web font that is available online via services such as Google Fonts and Typekit.

Please see the Custom CSS Overrides article.