A variable is used to store any value that you like.
You can reuse variable in any block of code in your PHP script.
PHP variables must start with a dollar ($) sign.
PHP Variable Syntax
Below is an example of how to use variables in PHP:
The above code will output the following on your web browser:
As you can see above variables are not declared first before you can use it. PHP is a loosely type language and all you need is to declared the variable properly.
PHP variables must start with letters and underscore only. The same as other language, PHP variable must not contain spaces.