How can users send message to admin?

Hello everyone i want to create an interaction between a users and site admin where users can send message to admin, i have tried using chat application in node js but was able to send message to another user as both users have same html template, i am unable to create this can any one help me with this thank you in advance. i have this app.js

var express = require('express');

var app = express();
app.set('port', process.env.PORT || 9000);
var server = require('http').Server(app);
var io = require('socket.io')(server);
var port = app.get('port');

app.use(express.static('public'));

server.listen(port, function () {
    console.log("Server listening on: http://localhost:%s", port);
});

app.get('/', function (req, res) {
    res.sendFile(__dirname + '/index.html');
});

via akhil reddy