Why doesn't php5.6 want to work on ubuntu 16.04?

Question

linux

In general, I installed LAMP, installed the php5.6 version, and decided to check if php is working.
In the address I enter http://localhost/web/index.phpa letter there, there is nothing, although the code says

<?php

echo "Hello, World!";

?>

The /var/www/html/web folder itself shows that there is an index.php file there. But for some reason it doesn't work. What is the reason for this?
Terminal showing php version

[email protected]:~$ php --version
PHP 5.6.23-1+deb.sury.org~xenial+2 (cli) 
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies
[email protected]:~$