add_action('init', function() {
  register_post_type('shops', [
    'label' => 'お店',
    'labels' => [
      'all_items' => 'お店一覧'
    ],
    'public' => true
  ]);
});

<?php
add_action('admin_print_footer_scripts-post-new.php', function() {
  // カスタム投稿タイプがshopのとき
  if (get_post_type() === 'shops') : ?>
    <script>
    (function($) {
      $('#acf-postal_code .button').on('click', function() {
        $.ajax({
          type: 'get',
          url: '//api.zipaddress.net',
          data: {
            zipcode: $('#acf-field-postal_code').val()
          },
          timeout: 10000
        })
        .done(function(res) {
          if (res.code === 200) {
            $('#acf-field-address').val(res.data.fullAddress);
          } else {
            $('#acf-field-address').val('存在しない住所です。');
          }
        });
      });
    })(jQuery);
    </script>
<?php
  endif;
});