woocommerce_before_order_notes │ action-hook │ WC 1.0

Usage

add_action( 'woocommerce_before_order_notes', 'wp_kama_woocommerce_before_order_notes_action' );

/**
 * Function for `woocommerce_before_order_notes` action-hook.
 * 
 * @param  $checkout 
 *
 * @return void
 */
function wp_kama_woocommerce_before_order_notes_action( $checkout ){

	// action...
}

$checkout

-

Where the hook is called

<?php do_action( 'woocommerce_before_order_notes', $checkout ); ?>

Where the hook is used in WooCommerce