How to find product Id and variant Id?

When you click a product in your Shopify dashboard, you see that the link has a unique ID for that specific product.

In case your product has variants and you want to know your variants ID too, then click on a variant and the new page has the variant ID now in addition to product ID.

Note that this product ID and variant ID are used as a tag for each customer who leaves an email on that certain product ID-variant ID.