In the WooCommerce admin area when you are editing the product data there is a “Linked Products” tab. Products can be related to each other in three ways: Up-Sells, Cross-Sells, or by having the same tags or categories.
Up-Sells ↑ Back to Top
Up-sells are products which you recommend instead of the currently viewed product, for example, products that are more profitable or better quality or more expensive. Depending on your site’s template these products will display on the single product page underneath the product’s description.
Cross-Sells ↑ Back to Top
Cross-sells are products which you promote in the cart, based on the current product. Depending on your site’s template they will display on the cart page underneath the cart products table with a thumbnail image.
Related Products ↑ Back to Top
Related products is a section on some templates that pulls other products from your store that share the same tags or categories as the current product. These products can not be specified in the admin, but can be influenced by grouping similar products in the same category or by using the same tags.
Examples ↑ Back to Top
Here is an example product page using the Athena theme that shows the Up-Sells and the Related Products. Each time the page is reloaded the products shown in the “Related Products” section will be different.
Here is an example cart page using the Athena theme and showing cross-sell items.