how to extra 0 before number in php code example

Example 1: prepend 0 to number php

str_pad($month, 2, '0', STR_PAD_LEFT);

Example 2: php add 0 before number

$number = 4;
str_pad($number, 2, '0', STR_PAD_LEFT); // returns 04

$number = 14;
str_pad($number, 2, '0', STR_PAD_LEFT); // returns 14