With the complementary products feature you can dynamically show complementary products on your product page. This increases the chance for customers to find and purchase additional products related to what they’re already interested in.

This also requires the official Shopify Search and Discovery App to be installed. If you already installed that app to set up advanced filtering then you’re ready to go. If not you’ll have to do it now.

Once installed go to “Apps” in your Shopify admin and select “Search and Discovery”. Select “Recommendations” and from the list of products select a product to which you wish to add complementary products. You can set that for all your products or just some of them.

Now you just need to go to the Theme Customizer, select the product template, and add the “Complementary Products” block to it. In the block settings, you can also set the number of products you want to show as well as the heading.

The Related Products feature works in the same way. The difference is that even if you don’t set related products it will automatically try to show the products that are related. You can disable this per product by ticking the “Hide auto-generated recommendations” checkbox.

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