The Complementary Products feature allows you to dynamically display related products on your product pages. This increases the likelihood that customers will discover and purchase additional items related to their current interests.

This feature also requires the official Shopify Search and Discovery App. If you’ve already installed the app for advanced filtering, you’re all set. If not, you’ll need to install it first.

To set it up:

1. Go to Apps in your Shopify admin and select Search and Discovery.
2. Click on Recommendations.
3. From the list of products, choose a product to which you want to add complementary items.
4. You can apply this to all your products or select specific ones.

Next, go to the Theme Customizer, select the Product template, and add the “Complementary Products” block. In the block settings, you can customize the number of products to display as well as the heading.

The Related Products feature works similarly to the Complementary Products feature. The key difference is that even if you don’t manually set related products, the system will automatically display related items. If you prefer to disable this for specific products, simply tick the “Hide auto-generated recommendations” checkbox.

To add Related Products to your product page, go to the Theme Customizer, select the Product template, and then add the “Related Products” section.