Add a shipping method called Cash on Delivery Shipping Method (for example), go to
WooCommerce > Shipping > Shipping zones > Italia ( or another country ) > edit > Add shipping method
in this case with a flat rate of 12,2 net that with 22% VAT become € 14.88
then go to WooCommerce > Settings > Payments > Cash on delivery
click Manage and go to Enable for shipping methods
add the just created method Cash on Delivery Shipping Method
Only if the cash on delivery payment is selected, the cash on delivery shipping method appears and so the extra fee is activated, WITH NO need to activate plugins external to WooCommerce
