federated-wordpress-customizations/woocommerce/thank_you_page_customizations.php

<?php

add_action( 'woocommerce_before_thankyou', 'federated_thank_you_page_message' );

function federated_thank_you_page_message( $order_id ) {
	echo '<h3>Please check your email to confirm account creation. Your core is now being provisioned.</h3>';
}