Try the following to display a custom text in "View Order" pages:
add_action('woocommerce_order_details_after_order_table', 'action_order_details_after_order_table', 10, 4 );
function action_order_details_after_order_table( $order, $sent_to_admin = '', $plain_text = '', $email = '' ) {
// Only on "My Account" > "Order View"
if ( is_wc_endpoint_url( 'view-order' ) ) {
printf( '<p class="custom-text">' .
__("To cancel your license within the 30 day trial period click on %s" ,"woocommerce"),
'<strong>"' .__("Refund my entire order", "woocommerce") . '"</strong>.</p>' );
}
}
Code goes in function.php file of your active child theme (or active theme). Tested and works.