You can create a separate WooCommerce product for the physical gift cards. This can be a Simple Product if you have a fixed amount, or a Variable Product if you want to offer multiple amounts (Variations). This is similar to how Amazon works (they sell an eGift card and a physical gift card, as separate products).
If you would like to purchase plastic gift cards from a vendor, most will generate random numbers for you and provide a CSV file that can be imported into WooCommerce. Then when a customer purchases a physical gift card you will mail the plastic gift card to them and it can be redeemed in your store since you imported the numbers.
There aren’t any strict requirements for physical gift cards, just make sure they provide you with a list of codes and amounts in a spreadsheet so that you can import them into the system. Also, ensure they do not create sequential numbers for you (most do not since they are creating gift cards).
To add custom fields to the physical gift card product (such as Recipient and Message) you can use another third party plugin such as WC Fields Factory.
Hope this helps, let me know if you have any other questions!
