Creating my account system in CodeIgniter 4 involves several steps, including setting up the database, creating controllers, models, and views, and implementing user registration, login, and logout functionalities. Below is a simple tutorial to guide you through the process. Make sure you have CodeIgniter 4 installed on your server before starting.

Step 1: Database Setup

Create a database and a table to store user information. 

Step 2: CodeIgniter Configuration

Make sure your CodeIgniter configuration files are set up correctly, especially the App/Config/Database.php configuration file with the database connection details.

Step 3: Controller

Create a controller for handling user registration, login, and logout. In your app/Controllers/myaccount/MyAccount.php file:

<?php
namespace App\Controllers\myaccount;

use App\Controllers\BaseController;

use App\Models\login\LoginModel;

class MyAccount extends BaseController {

    public function __construct() {
        $db                 = db_connect();
        $this->session      = \Config\Services::session();
        $this->login        = new LoginModel($db);

        $this->ip_address   = $_SERVER['REMOTE_ADDR'];
        $this->datetime     = date("Y-m-d H:i:s");

    }

    public function index() {
        $this->myaccount();
    }

    public function myaccount() {
        if($this->session->get('login_status')) {
            $data                   = [];
            $data ["result"]        = $this->login->getEntry(['id' => $this->session->get('login_id')]);
            $data ['content_title'] = 'My Account';
            echo view('myaccount/myaccount', $data);
        } else {
            return redirect()->to(base_url('login'));
        }
    }

    public function update() {
        $id                 = $this->request->getPost('id');
        $name               = $this->request->getPost('name');
        $email              = $this->request->getPost('email');
        $password           = $this->request->getPost('password');
        $mobile_number      = $this->request->getPost('mobile_number');

        $where      = [
        'email'  => $email,
                'id !='  => $id,
    ];
        $has_account = $this->login->getEntry($where);
        if($has_account) {
            $json = [
            'status'    => false,
                    'message'   => showDangerMessage("Entered email address is already registered"),
        ];
        } else {
            if($password) {
                $data = [
                'name'              => $name,
                        'email'             => $email,
                        'password'          => md5($password),
                        'mobile_number'     => $mobile_number,
                        'ip_address'        => $this->ip_address,
            ];
            } else {
                $data = [
                'name'              => $name,
                        'email'             => $email,
                        'mobile_number'     => $mobile_number,
                        'ip_address'        => $this->ip_address,
            ];
            }

            $result = $this->login->updateEntry(['id' => $id], $data);
            if($result) {
                $result = $this->login->getEntry(['id' => $id]);
                if($result) {
                    $data = [
                    'login_id'              => $result->id,
                            'login_email'           => $result->email,
                            'login_name'            => $result->name,
                            'login_mobile_number'   => $result->mobile_number,
                            'user_status'           => $result->status,
                            'login_status'          => TRUE,
                ];
                    $this->session->set($data);
                }
                $json = [
                'status'    => true,
                        'message'   => showSuccessMessage("Your account has been updated successfully"),
            ];
            } else {
                $json = [
                'status'    => false,
                        'message'   => showDangerMessage("Something went wrong. Please try again!"),
            ];
            }
        }
        echo json_encode($json);
    }
}

Step 4: Views

Create views for user registration and login in the app/Views/myaccount directory

<?php $session    = \Config\Services::session();
?>
<!DOCTYPE html>
<html lang="en">

<head>
    <title><?php echo $content_title; ?></title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/css/bootstrap.min.css">
    <script src="https://cdn.jsdelivr.net/npm/jquery@3.7.1/dist/jquery.slim.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.1/dist/umd/popper.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/js/bootstrap.bundle.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
</head>

<body>
    <div class="jumbotron text-center">
    <h1>Welcome <?php echo $session->get('login_name'); ?></h1>
    <p>My Account</p>
    </div>
    <div class="container">
        <div class="row">
            <div class="col-sm-3">
                
            </div>
            <div class="col-sm-6">
                <div class="message"></div>
                <form id="form-update-myaccount" method="post" autocomplete="off">
                    <input type="hidden" name="id" value="<?php echo $result->id; ?>">
                    <div class="form-group">
                        <label>Name</label>
                        <input type="text" class="form-control" id="name" name="name" placeholder="Name" value="<?php echo $result->name; ?>" required>
                    </div>
                    <div class="form-group">
                        <label>Email</label>
                        <input type="email" class="form-control" id="email" name="email" placeholder="Email" value="<?php echo $result->email; ?>" required>
                    </div>
                    <div class="form-group">
                        <label>Password</label>
                        <input type="password" class="form-control" id="password" name="password" placeholder="Password">
                    </div>
                    <div class="form-group">
    <label>Mobile No.</label>
                        <input type="text" class="form-control" id="mobile_number" name="mobile_number" placeholder="Mobile No." value="<?php echo $result->mobile_number; ?>" maxlength="10" required>
                    </div>
                    <div class="form-group">
                        <button type="submit" id="btn-login" class="btn btn-success">Update</button>
                    </div>
                </form>
            </div>
        </div>
    </div>

    <script>
    $(document).ready(function() {
        $("#form-update-myaccount").on("submit", function(e) {
            e.preventDefault();
            let data = $(this).serialize();
            $.post('<?php echo base_url("myaccount/update"); ?>', data, function(result) {
                $(".message").html(result.message);
            }, 'json');
        });
    });
    </script>
</body>

</html>

Step 5: Routes

Define the routes in app/Config/Routes.php:

// My Account Routes
$routes->group('myaccount', function($routes) {
    $routes->get('/',                   'myaccount\MyAccount::index', ['filter' => 'auth']);
    $routes->post('update',             'myaccount\MyAccount::update', ['filter' => 'auth']);
});