PHP is server side language it execute web server  and resulting html send to the browser .

PHP save file with file_name.php

All php code run in php tag (<?php   write_code   ?>)  where echo used to display text to web page

index.php -This is file extension


<DOCTYPE html>


<meta charset="utf-8">

<title> hello php </title>



<p><?php echo "hello word" ?> </p>



Php code writen within in php tag


hello word

 php is write in side php code .php code written only php file if you write php inside the html , css ,or javascript file then php code not run . php code run only php file and php file run on the server


Localhost server mean it run php only for you and it working on you local network that can we easily access your localhost file in your mobile

Localhost server can not serve out side you local area network 

Some server name that can be use in your computer for  development time of php