syntax error, unexpected add_action wordpress

I'm getting this error message when trying to add a hook to include certain text in the email that is sent when an order is placed.

syntax error, unexpected add_action wordpress

            function add_order_email_instructions() {
echo "Mensagem de teste";
  }


  add_action( 'woocommerce_email_before_order_table', 'add_order_email_instructions', 10, 2 );