How to changed “Thank you. Your order has been received” title text on WooCommerce : Order Thank you page ?
Change main default title text on Order thank you page very easy, you can achieve it by using woocommerce_thankyou_order_received_text WooCommerce filter in WordPress.
On woocommerce_thankyou_order_received_text filter hook your function and return your specific customized text which you or your want to show on Order Thank you page in WooCommerce.
Add following code on your active theme functions.php file with change your desire text set in $added_text.
Dear ' .$user->first_name.' '.$user->last_name.', Thank you for your purchase!'; return $added_text ; } ?>