Data-driven product recommendations for your online store are now included by default in the new versions of the following Shopify free themes:

Enable the section to show product recommendations to your customers. The product recommendations are based on products that are commonly purchased together and similar products, so that customers see the most relevant suggestions.

Learn more about product recommendations from the Shopify Help Center at https://help.shopify.com/manual/using-themes/change-the-layout/theme-settings/product-recommendations