PHP is a programming language, generally used for website development. Unlike HTML, PHP is a server-side scripting language. This allows you to accomplish a lot of things that you are otherwise unable to do. While you can build a website entirely with HTML, PHP allows you to build more complex websites and more complex features within it. Most advanced tools within your website will rely upon PHP to operate.
PHP can be an invaluable tool for your website development. Your website may reach a point where, in order to continue to evolve, you will need to employ the help of a PHP programmer. Thankfully, PHP is a very popular programming language, and lots of people are capable of using it to an extent. Choosing from amongst your options can be difficult, but you should make sure that you find a programming team which is proficient in PHP programming, otherwise you may find the costs increasing above the potential gains.