Digital downloads — like eBooks, music files, images, sewing patterns, and fonts — work well as standalone purchases, or as add-ons to physical products or services. For example, if you sell music courses online, you might also sell digital sheet music. Or if you crochet baby toys, you could sell downloadable patterns for those who also enjoy crafting.
https://jetpack.com/blog/how-to-sell-digital-products-on-wordpress-with-woocommerce/#more-165527