Yes! This is currently an option on our desktop website story editor (*we're working on a feature for the Inkitt Writing app, so stay tuned).
With our cover editor tool, you can create and edit your own cover picture, having the ability to change the font for both the title and author name. You can edit size, color, and also make text bold or italicized.
*NOTE: The story name and author name pull straight from the title and your "Display Name" in your personal settings.