Payment Processing Fee

wordpresspaymentfee.php

<?php
//Payment Gateway Selection
  
add_action( 'woocommerce_cart_calculate_fees', 'bbloomer_add_checkout_fee_for_gateway' );
  
function bbloomer_add_checkout_fee_for_gateway() {
    $chosen_gateway = WC()->session->get( 'chosen_payment_method' );
     if ( $chosen_gateway == 'paypal' ) {
      WC()->cart->add_fee( 'PayPal Fee', 5 );
   }
}
  
// Part 2: reload checkout on payment gateway change
  
add_action( 'woocommerce_review_order_before_payment', 'bbloomer_refresh_checkout_on_payment_methods_change' );
  
function bbloomer_refresh_checkout_on_payment_methods_change(){
    ?>
    <script type="text/javascript">
        (function($){
            $( 'form.checkout' ).on( 'change', 'input[name^="payment_method"]', function() {
                $('body').trigger('update_checkout');
            });
        })(jQuery);
    </script>
    <?php
}

?>