Not able to add product attribute on Backend

To Whom it may concern :

We have few Product Package Allow user to add different taste of pet food.
https://www.petmarket.com.hk/product/beaphar-%e8%85%8e%e8%87%9f%e4%bf%9d%e5%81%a5%e9%85%8d%e6%96%b9-%e4%bb%bb%e9%81%b8%e5%8f%a3%e5%91%b3x48-100g/

The attribute does neither apprear in the database table eav_attribute nor on the website on the product page nor in the backend.

I have already read several tutorials, change my code multiple times, but it just doesn’t work.