XML Comment

XML comments are similar to HTML comments.
It is used to make the codes more understandable for other developers to use.
Comments not consider as a XML code.
These comments add notes or lines for the purpose of better understanding the XML code.
XML is known as self-describing data but sometimes XML comments are necessary.
Comments begin with a 
XML Comments will ignored by the parser not to be validated.

Syntax

An XML comment should be written as:

<!-- Write your comment-->

C# Comment

Learn - XML tutorial - XML Comments - XML examples - XML programs

Doesn't use the comments before an XML declaration.
We can use these comments anywhere in XML document except within attribute value.
Don't nest the comments inside the other.