how to make comments in php code code example

Example 1: comment in php

<?php
 /*
    echo 'This is a test'; /* This comment will cause a problem */
 */
?>

Example 2: comment in php

<?php
// Author : https://www.codedweb.org/
// This is a single-line comment
# This is also a single-line comment in unix and linux
  
/*
This is a Multi-lines comment block
by this way you can add muliple lines on it. 
lines
*/
  
// You can also use comments to leave out parts of a code line
$var = 2 /* + 12 */ + 2;
echo $var;
?>