PHP variable declaration is very easy from other language. In PHP all variables begin with the symbol $. It is not necessary to the begin in define variable.
There are no variable types in php. It can automatically detect when you declare any variable.
Oh! I forgot to tell you how can start php coding.Its very simple tag, first you write ‘<?php’ and end with  ‘?>’ . Between starting and ending tag you will declare your variable.

Example:

<?php

$a = 1;
$b = 3.34;
$c = “Hello World”;
echo $a,”<”,$b,”",$c;
?>

Here ‘echo’ use for see output. So, don’t worry now you can start your coding.

PHP means Hypertext Preprocessor; It can be embedded into HTML and generally runs on a web server, which needs to be configured to process PHP code and create web page content from it.this means that it includes variables, conditional statements, loops, functions… It is not a tag language such as HTML, XML or WML. PHP was originally created by Rasmus Lerdorf in 1995[1] and has been in continuous development ever since.
How to work php with server and web browser:
But unlike Java or JavaScript that are run using the web browser, PHP is run on the server, which allows us to access server resources, e.g. a data base. The PHP program is run on the server and the result is sent to the web browser. The result is usually an HTML page but it could also be a WML page.