create a function for woocommerce to add a "cash on delivery" support which will have a fee of 2$.

add_filter( 'woocommerce_available_payment_gateways', 'bbloomer_unset_cod_for_virtual' );
 
function bbloomer_unset_cod_for_virtual( $available_gateways ) {
global $woocommerce;
 
// Set the ID of the gateway to be removed here
$unset_gateway = 'cod';
 
if ( isset( $available_gateways[$unset_gateway] ) && $woocommerce->cart->needs_shipping() ) {
unset( $available_gateways[$unset_gateway] );
}
 
return $available_gateways;
}