Actionable Message for Playbook

Here is the complete example code that can be copied and pasted in the Compose action of the flow.

<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <script type="application/adaptivecard+json">
{
  "$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
  "type": "AdaptiveCard",
  "version": "1.0",
  "originator": "@{variables('Originator id')}",
    "body": [
        {
            "type": "Image",
            "separator": true,
            "url": "@{variables('Image URL')}"
        },
        {
            "type": "Container",
            "items": [
                {
                    "type": "TextBlock",
                    "size": "Medium",
                    "weight": "Bolder",
                    "text": "@{triggerOutputs()?['body/subject']}"
                },
                {
                    "type": "TextBlock",
                    "text": "Requested by **@{outputs('Get_the_Creator_record')?['body/fullname']}** <<@{outputs('Get_the_Creator_record')?['body/domainname']}>>",
                    "wrap": true
                },
                {
                    "type": "FactSet",
                    "facts": [
                        {
                            "title": "Date Created:",
                            "value": "{{DATE(@{outputs('Get_the_Playbook_record')?['body/createdon']}, LONG)}}"
                        },
                        {
                            "title": "Project:",
                            "value": "[@{outputs('Get_the_Opportunity_record')?['body/name']}](@{variables('Open Opp URL')}@{outputs('Get_the_Opportunity_record')?['body/opportunityid']})"

                        },
                        {
                            "title": "Start date:",
                            "value": "@{triggerOutputs()?['body/scheduledstart']}"
                        },
                        {
                            "title": "End date:",
                            "value": "@{triggerOutputs()?['body/scheduledend']}"
                        }
                    ]
                }
            ]
        }
    ],
    "selectAction": "Submit",
    "actions": [
        {
            "type": "Action.ShowCard",
            "id": "confirm",
            "title": "Confirm",
            "card": {
                "type": "AdaptiveCard",
                "body": [
                    {
                        "type": "Input.Text",
                        "id": "commentInput",
                        "placeholder": "Reason (optional)",
                        "isMultiline": true
                    }
                ],
                "actions": [
                     {
                      "type": "Action.Http",
                      "title": "Submit",
                      "method": "POST",
                      "url": "@{variables('Receiving Flow URL')}",
                      "headers": [
                        {
                          "name": "Authorization",
                          "value": ""
                        }
                      ],
                      "body": "{'taskId':'@{triggerOutputs()?['body/activityid']}','response':'Confirmed','reason':'{{commentInput.value}}','userName':'@{outputs('Get_the_Creator_record')?['body/domainname']}'}"
                    }
                ],
            }
        },
        {
            "type": "Action.ShowCard",
            "id": "reject",
            "title": "Reject",
            "card": {
                "type": "AdaptiveCard",
                "body": [
                  {
                        "type": "Input.Text",
                        "id": "reasonInput",
                        "placeholder": "Reason (required)",
                        "isMultiline": true,
 "spacing": "none"
                    }
                ],
                "actions": [
                    {
                      "type": "Action.Http",
                      "title": "Submit",
                      "method": "POST",
                      "url": "@{variables('Receiving Flow URL')}",
                      "headers": [
                        {
                          "name": "Authorization",
                          "value": ""
                        }
                      ],
                      "body": "{'taskId':'@{triggerOutputs()?['body/activityid']}','response':'Rejected','reason':'{{reasonInput.value}}','userName':'@{outputs('Get_the_Creator_record')?['body/domainname']}'}"
                    }
                ],
            }
        },
    ],
}
</script>
</head>
<body>
This message was created by an automated workflow in Power Automate. Do not reply. 
</body>
</html>