Workflow: Manual Send

{
    "nodes": [
        {
            "name": "On clicking 'execute'",
            "type": "n8n-nodes-base.manualTrigger",
            "position": [
                240,
                300
            ],
            "parameters": [],
            "typeVersion": 1
        },
        {
            "name": "Extract domain name",
            "type": "n8n-nodes-base.function",
            "position": [
                700,
                300
            ],
            "parameters": {
                "functionCode": "\/\/ Take email and extract the domain name \nvar email = ($json[\"email\"]);\nvar name   = email.substring(0, email.lastIndexOf(\"@\"));\nvar domain = email.substring(email.lastIndexOf(\"@\") +1);\n\n\/\/To display the final domain name. (result)\n\nreturn [{\n  json: { domain }\n}]"
            },
            "typeVersion": 1
        },
        {
            "name": "Sample email",
            "type": "n8n-nodes-base.set",
            "position": [
                460,
                300
            ],
            "parameters": {
                "values": {
                    "string": [
                        {
                            "name": "email",
                            "value": "email@domain2.com"
                        }
                    ]
                },
                "options": [],
                "keepOnlySet": true
            },
            "typeVersion": 1
        }
    ],
    "connections": {
        "Sample email": {
            "main": [
                [
                    {
                        "node": "Extract domain name",
                        "type": "main",
                        "index": 0
                    }
                ]
            ]
        },
        "On clicking 'execute'": {
            "main": [
                [
                    {
                        "node": "Sample email",
                        "type": "main",
                        "index": 0
                    }
                ]
            ]
        }
    }
}