Hi Sue, the product purchase in Woocommerce if it's integrated54 to Convertkit. You have the option to add it to visual automation via product or via tag, form, or sequence.
https://share.getcloudapp.com/z8uLrmPr59
We call product tags via liquid code. For your reference.
https://help.convertkit.com/en/articles/2502633-basic-email-personalization-with-liquid-faqs48
https://help.convertkit.com/en/articles/2502501-advanced-email-personalization-with-liquid43