My Joomla website does not run the index.php and instead of displaying the content of the site when accessing the domain, download the index.php file

By entering the website I download the index.php instead of showing the content of the site. I am using joomla and this is the content of the index.

<?php

define('JOOMLA_MINIMUM_PHP', '5.3.10');

if (version_compare(PHP_VERSION, JOOMLA_MINIMUM_PHP, '<'))
{
die('Your host needs to use PHP ' . JOOMLA_MINIMUM_PHP . ' or higher to run 
this version of Joomla!');
}

// Saves the start time and memory usage.
$startTime = microtime(1);
$startMem  = memory_get_usage();


define('_JEXEC', 1);

if (file_exists(__DIR__ . '/defines.php'))
{
include_once __DIR__ . '/defines.php';
}

if (!defined('_JDEFINES'))
{
define('JPATH_BASE', __DIR__);
require_once JPATH_BASE . '/includes/defines.php';
}

require_once JPATH_BASE . '/includes/framework.php';

// Set profiler start time and memory usage and mark afterLoad in the 
profiler.
JDEBUG ? JProfiler::getInstance('Application')->setStart($startTime, 
$startMem)->mark('afterLoad') : null;

// Instantiate the application.
$app = JFactory::getApplication('site');

// Execute the application.
$app->execute();

?>