Contact Form 7 add confirm
  1. Contact Form 7 add confirm install and activate
  2. modify below on plugins file
    https://ja.wordpress.org/support/topic/contact-form-7%E3%82%A2%E3%83%83%E3%83%97%E3%83%87%E3%83%BC%E3%83%88%E3%81%A7contact-form-7-add-confirm%E3%81%8C%E5%8A%B9%E3%81%8B%E3%81%AA%E3%81%84/