PHP snippet to add a extra fee to the checkout for every payment gateway.
You can copied and pasted in your theme’s functions.php file and get solution for this.
PHP Code
/**
* @snippet How to add checkout payment Fee for a payment gateway - WooCommerce
*/
add_action( 'woocommerce_cart_calculate_fees', 'mycode_add_checkout_fee' );
function mycode_add_checkout_fee() {
// Edit "Payment Fee" and "3" below to control Label and Amount
WC()->cart->add_fee( 'Payment Fee', 3 );
}