Choosing a PHP Editor

PHP files can be edited using any text editor but you would prefer a bit advanced editor when you engage in your PHP development, one at least has syntax highlighting option so that you can distinguish between different PHP statements.

If you are on Windows, Notepad++ can be a good option. It has many features like auto-completion in addition to syntax highlighting. If you are on Linux gedit would be good.

Using an IDE (Integrated Development Environment)

An IDE is an application that integrates more development tools like a debugger, an interpreter, a version control system with the editor. So it lets you execute many development tasks at one place. When you build more advanced PHP applications, an IDE can be helpful. EasyEclipse for PHP is a good IDE if you want to try one out.