Change order note label in woocommerce checkout page

For our customization want to change woocmmerce order notes label in checkout page then place the following snippet in functions.php within your theme folder!.

add_filter( 'woocommerce_checkout_fields' , 'change_order_note_label_in_woocommerce_checkout_page' );
function change_order_note_label_in_woocommerce_checkout_page( $fields ) {
     $fields['order']['order_comments']['label']="Special Insructions";
     return $fields;
}

Have any doubt, then comment here!