You can start using PHP in the following ways.
Find web hosts that support PHP and MySQL.
Install PHP and MySQL by installing the webserver on your own PC.
Use a PHP supported web host.
If you already have PHP active on your server, you don't need to do anything else to set up PHP.
Just create some files with the .php extension and put them in your web directory and run them from the browser then the server will automatically parse them for you.
You don't have to bother compiling anything or installing extra tools.
Since PHP is free, most web hosts support PHP.
Set up PHP on your own PC
However, if your server does not support PHP, you need to do the following:
Install the webserver
Install the database. E.g. MySQL
To learn more about installing PHP, visit PHPnet, PHP's official site:
To install PHP, we recommend installing the AMP (Apache, MySQL, PHP) software stack. Because it is always available for all operating systems. You will see many types of AMPs in the market which are highlighted below:
WAMP - for Windows
LAMP - for Linux
MAMP - for Mac
SAMP - For Solaris
FAMP - For FreeBSD
XAMPP (Cross, Apache, MySQL, PHP, Perl) - for cross-platform. It also adds some other components. For example- FileZilla, OpenSSL, Webalizer, OpenSSL, Mercury Mail etc.
Server download links for different platforms