PHP comes standard with many built-in functions. They give us an easier way to implement and repeat popular tasks throughout a program. A popular example is the echo function.

Many more are documented at https://www.php.net/docs.php. In addition to a description of what the function does, the documentation for each function denotes:

• The name of the function
• Required parameters and their types
• Optional parameters (in square brackets, []), their types, and default values
• The return type of the function (after the final colon, :)