Generally there are 2 ways:
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.
ArtStation Pro offers CSS overrides. This enables you to use the
@import statement to import any webfont that is available online via services such as Google Fonts and Typekit.
Please see the Custom CSS Overrides article.