如果您需要使用Add-in UI外观来呈现Adaptive card JSON，则需要通过添加适当的外观元素来自定义Adaptive card JSON。以下是一个示例代码片段，说明如何使用ActionSet来自定义Adaptive card JSON以呈现Add-in UI外观。

{
  "type": "AdaptiveCard",
  "version": "1.0",
  "body": [
    {
      "type": "TextBlock",
      "text": "Choose your payment method:",
      "size": "Medium",
      "weight": "Bolder"
    },
    {
      "type": "ActionSet",
      "actions": [
        {
          "type": "Action.Submit",
          "title": "Pay with Credit Card",
          "data": { "PaymentMethod": "Credit Card" }
        },
        {
          "type": "Action.Submit",
          "title": "Pay with PayPal",
          "data": { "PaymentMethod": "PayPal" }
        }
      ]
    }
  ]
}

这个示例代码片段使用TextBlock和ActionSet元素来自定义Adaptive card JSON以呈现Add-in UI外观。您可以根据需求添加其他元素来自定义Adaptive card JSON。