How can I setup custom fonts?

The app has a small selection of fonts pre-configured.  You can add more fonts in the "Settings" page:

In the "Font settings" section, you can click on "Upload font" or "Add Google font":

Google font

You can search in all of the available Google fonts.  Select the font you want to add and click on "Add Google font":

Upload font

You can also upload your own font. Click on "Upload font", enter a name for your font (The name will be used in the font preview) and upload at least one font variant:

Product options

On your product options configuration you can then use the configured fonts. 

Show font selector

You can show a font selector by adding a new option of type "Font":

The font selector will show each font name rendered in the actual font:

Connect to live preview

In the live preview section, if you want to update the font for a text layer. Connect the font option with the font selector: