In Magento you can add any attribute by going into the admin panel go to STORES > Attributes > Product > Add new attribute. Here you can add any functional attributes you want. https://docs.magento.com/user-guide/catalog/product-attributes-add.html
After completing the above preparation steps, you can create a file with the extension CSV for example demo.csv.
Next get the sku of the product you want to change.
then get the attribute code the attribute you want to add or change by Admin panel > STORES > Attributes > Product > my_attribute_name
After getting the attribute code name that you just added in the product, add it to your csv file which will have the form
Next, after editing the attribute as you want, save the file and update the product by
Admin panel > SYSTEM > Import > Pomegranate selected as in the photo
and load the file you want to change and then check the result again.I wish you success.