How many types of comments are there in PHP?

There are two types of comments in PHP. They are

1. One Line comments (// or #)
2. Multiple Line comments (/* */)

The "one-line" comment styles only comment to the end of the line or the current block of PHP code, whichever comes first.
Eg:

      

     <?

      // echo 'Your code upto end of the line'; 

     ?>

     <?

     # echo 'Your code upto end of the line';  

     ?> 

Multiple Line comments (/* */) are used to comment a large block of PHP code.
Ex: <?

 /*
    echo 'This is a test';

    echo 'This is a test line2';

       echo 'This is a test line 3';
 */
?>