Maybe it is a little hard to understand, but XML does not DO anything.
This note is a note to Ted, from Jane, stored as XML:
<body>Don't forget me this weekend!</body>
The note is quite self-descriptive. It has sender and receiver information. It also has a heading and a message body.
But still, this XML document does not DO anything. XML is just information wrapped in tags. Someone must write a piece of software to send, receive, store, or display it.