To add article numbers to a product in WooCommerce, there are several ways you can do this. Here are some steps you can follow:
Go to the WordPress admin page of your website and log in.
Click on "Products" in the left menu and select "All Products".
Find the product you want to add the article number to and click on "Edit".
Scroll down to the "Product Data" section.
Depending on the theme you are using, the "Product Data" section may look different. In most cases, you can find the "SKU" (Stock Keeping Unit) or "Product Number" section. This is where you can enter the article number.
Enter the article number in the designated field. The article number can be a unique identification number that you can determine yourself.
Click on "Update" to save the changes.