Floating cart shipping settings
Shipping option in the cart modal is visible once shipping is enabled in WooCommerce settings. Shipping address option allows the user to calculate the shipping cost based on the shipping address from the cart modal.
Note: Shipping option is only visible if the shipping is enabled in the WooCommerce settings.
Enable WooCommerce shipping calculator
To enable the shipping option, go to WooCommerce > settings > shipping > shipping options, then check on enable the shipping calculator on the cart page option.
Once you click the enable shipping calculator on the cart page option, make sure to save the changes.