Code that seems clear at the time of writing can seem like a hopeless tangle when you try to amend it six months later. Adding comments to your code as you write can save you time later on and make it easier fo other programmers to work with your code.
A comment is a text in a script that is ignored by the PHP engine. Comments can be used to make the code more readable or to annotate a script.
Single-line comments begin with two forward slashes (//) or
a single hash sign(#).
The PHP engine ignores all text between these marks and either the end of the line or the PHP close tag:
// this is a comment
# this is another comment
Multiline comments begin with a forward slash followed by an asterisk (/*) and end with an asterisk followed by a forward slash (*/):
this is a comment none of this will be parsed by the PHP engine