Return policy

Google is sending me error messages that I don’t have return policy listed in the meta data of my items. I do have a return policy that’s clearly listed on the website but I’m not finding where I add it into structured data fields.

If it’s relevant it’s the same for all digital products and then one policy for all physical products so I’m assuming I need to add it for each item?

Can anyone help with this?

The page I need help with: [log in to see the link]