WooCommerce shipping method

WooCommerce calculates shipping per package. A method receives one package and adds zero or more rates for that package.

Load and register

With Composer PSR-4 autoloading, defer registration until WooCommerce has loaded its shipping base class:

add_action( 'woocommerce_shipping_init', static function (): void {
    add_filter( 'woocommerce_shipping_methods', static function ( array $methods ): array {
        $methods['myplugin_carrier'] = MyPlugin\Shipping\CarrierMethod::class;
        return $methods;
    } );
} );

The array key must match the class $id. Register a class name; WooCommerce creates one object per zone-method instance.