您可以将以下代码写入活动主题的functions.php 要实现这一点：

// define the woocommerce_before_checkout_billing_form callback 
function action_woocommerce_before_checkout_billing_form( $wccs_custom_checkout_field_pro ) { 
    // Write your button code or any html here.... 
}; 

// add the action 
add_action( \'woocommerce_before_checkout_billing_form\', \'action_woocommerce_before_checkout_billing_form\', 10, 1 );