Not sure if I got it correctly. Do you mean you are trying to run our “Generate EANs automatically for all products from product IDs” tool but EANs are not created for the products? If that’s the case – is there any error displayed? If there is no error – do you see the “EAN generated for X products” message after you run the tool?
Please make sure that you have set the “Type” option in “WooCommerce > Settings > EAN” to “CODE 128”. After you save changes, the tool will be displayed in “Tools > Products > Generate EANs automatically for all products from product IDs” (again in “WooCommerce > Settings > EAN”, it’s a checkbox at the bottom of the page).