The tags may be such that they describe the content of the element. At the simplest level XML is just a way of marking up data such that it is self-describing. It provides a standardised means for storage and transport of data. The most common form of markup is used for elements. This single element can comprise any number of nested sub-elements.
Elements consist of two tags, an opening and a closing tag.
Text can be contained between the element tags and is considered part of the element. Empty elements are also supported. Elements can have attributes which further refine or modify element behaviour. Most elements identify the nature of the contents they surround. The logical structure of an XML document indicates how it is built, what elements can be included and in what order.