The licensing of fonts in distributed projects is important. We highly suggest the use of the built-in Google Fonts list because they are freely available for use on commercial projects. But if you do decide to use a custom imported font, you'll want to make sure that you hold the appropriate license for redistribution of that font within your project.
Google Fonts - Free
The entire catalog of Google Fonts are available right within Showit. You can also visually browse the catalog at https://fonts.google.com
How Fonts Work in Showit Designs
Custom fonts WILL transfer within a design as the uploaded WOFF format.
The font WILL act as a full functioning font within the Showit design (editable text).
The custom font WILL NOT appear in the user's media library (only in Design Settings).
The font WILL NOT be available for download within Showit.
Licensing a Custom Font
Even if you find a font on a site like Creative Market with a Commercial license option, it's always best to message the font owner to determine if it can be used within Showit under a license option they offer.