Operator are symbols to defines the processor to 
perform certain action. In other words: operators 
are used to performs operations on variables and values.

In PHP, many operators are as follows:
1) Assignment Operators (+, -, *, /, %)
2) Arithmetic Operators (+=, -=, *=, /=)
3) Relational Operators (>, <, >=, <=, ==, !=)
4) String Operators (. , .= ) 
5) Logical Operators (&&, ||, !)
6) Increment/decrement Operators (++, --)