how to call a simple post request and retrival of page example in php with curl?

$url = "https://www.example.com/login.php";
$data = array(
    'username' => 'myusername',
    'password' => 'mypassword'
);

// Initialize cURL session
$ch = curl_init();

// Set cURL options
curl_setopt($ch, CURLOPT_URL, $url); // URL to call
curl_setopt($ch, CURLOPT_POST, true); // POST request
curl_setopt($ch, CURLOPT_POSTFIELDS, $data); // POST data
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); // return response as string

// Execute cURL session
$response = curl_exec($ch);

// Check for errors
if(curl_errno($ch)) {
    echo 'Error: ' . curl_error($ch);
}

// Close cURL session
curl_close($ch);

// Process the response
echo "Response: " . $response;